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Septic Systems Online Book: This book (and website) explains septic system design, inspection, and test procedures, and explains the causes of defects in onsite waste disposal systems, septic tank problems, septic drainfield problems, checklists of system components and things to ask. Septic system design, alternative designs for difficult sites, septic maintenance and septic tank pumping schedules are provided.

Citation and brief quotation for purpose of review or reference are permitted. Use of this information in electronic form, soft copy, online web pages, in books or pamphlets for sale is reserved to the author. Review comments and content suggestions are welcome. Home buyers who want less technical advice should see the Home Buyer's Guide to Septic Systems. Also see The Septic Systems Home Page.

© Copyright 2009 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left.

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• piping connecting the building to the treatment tank
• a septic or treatment tank which retains solid waste
• piping connecting and conducting clarified effluent from the treatment tank to a distribution box
• a distribution box connecting the effluent line from the tank to the absorption system or "drain field"
• an absorption system which permits effluent to drain to soils below
• a bio-mat or bio-mass of pathogen-digesting bacteria which forms in soil below the absorption system.

Many variations on this general scheme are used, depending on local climate, soil conditions, available space, economy, and available materials. Special equipment and systems may be designed for problem or difficult sites such as rocky or wet ground, permafrost, or wet tropical marshlands.

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SEPTIC SYSTEMS ONLINE BOOK
INTRODUCTION
SEPTIC SYSTEM SAFETY WARNINGS
DEFINITIONS OF SEPTIC SYSTEM TERMS
SEPTIC SYSTEM DESIGN BASICS
  SEPTIC SOIL & PERC TESTS
  SEPTIC TANK SIZE
  SEPTIC TANK DEPTH
  SEPTIC TANK TEES
  SEPTIC & GREYWATER FILTERS
  SEQUENCING BATCH SEPTIC SYSTEMS
  SEPTIC DRAINFIELD SIZE
  SEPTIC DRAINFIELD SHAPE
  SEPTIC CLEARANCES
  SEPTIC TANK PUMPING FREQUENCY
  SEPTIC TANK PUMPING PROCEDURE
  INSPECTING SEPTIC TANKS
  MEASURE SCUM & SLUDGE
  CLEANING SEPTIC TANKS
  SEPTIC TREATMENTS
SEPTIC DESIGN ALTERNATIVES
  Wastewater Treatment Levels
  Wastewater Dispersal Methods
  Master List of Septic System Types
  AEROBIC SEPTIC SYSTEMS
  ALTERNATING BED SEPTIC SYSTEMS
  CESSPOOLS
  DRYWELLS
  SEPTIC EFFLUENT DISINFECTION SYSTEMS
  EVAPORATION-TRANSPIRATION SEPTIC SYSTEMS
  FIXED-FILM PROCESS SEPTIC SYSTEMS
  GRAVELLESS SEPTIC SYSTEMS
  MEDIA FILTER SEPTIC SYSTEMS
  SEPTIC & GREYWATER FILTERS
  SEQUENCING BATCH SEPTIC SYSTEMS
  MOUND SEPTIC SYSTEMS
  RAISED BED SEPTIC SYSTEMS
  SAND BED SEPTIC SYSTEMS
  SEWAGE TREATMENT SYSTEMS
  TOILET ALTERNATIVES
  SEPTIC SYSTEM PUMPS
SEPTIC INSPECTIONS
  SEPTIC FAILURE CAUSES
  SEPTIC TANK INSPECTION PROCEDURE
  SEPTIC DRAINFIELD FAILURES
  SEPTIC D-BOX INSPECTION
  SEPTIC FIELD INSPECTION
  SEPTIC DYE TESTS
  SEPTIC FAILURE SPOTS
SEPTIC SYSTEMS INSPECTION COURSE
SEPTIC INSPECTION TYPES & LEVELS
SEPTIC INSPECTION WORK SHEETS
SEPTIC FAILURE LAWSUIT
SEPTIC FLOOD RESPONSE
SEPTIC REFERENCES

More Reading:
Buyers' Guide: Home Buyer's Detailed Guide to Septic Systems - Buying a Home With a Septic Tank
Cesspools if you don't know what they are.
Components of a Septic System- the Basic Parts of a Conventional Septic Tank and Leachfield, a chapter in the Home Buyers Guide to Septic Systems
Drywells if you don't know what they are.
Don't Flush these things into a septic system
Safety Septic System, Septic Tank, & Cesspool Safety Warnings for Septic Inspectors, Septic Pumpers, and Homeowners.
Sketches of the Septic System Components Private Sewage Disposal Systems - Septic Drawing Library
What is a Septic System An Engineer's View - Types of treatment tanks, adsorption systems, pumps, and other special equipment are discussed in some further detail in this text

Septic Systems Online Book

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SAFETY WARNINGS - Septic Tank Safety Warnings for Septic Inspectors, Septic Pumpers, and Homeowners

This chapter is maintained at Septic System, Septic Tank, & Cesspool Safety Warnings for Septic Inspectors, Septic Pumpers, and Homeowners but text is repeated here for readers who scroll down rather than linking to the separate chapter.

Providing inspection and diagnosis of on-site waste disposal systems is an extremely valuable public service which helps protect people from expensive unanticipated septic system repair costs and helps protect public health by assuring sanitary disposal of sewage and gray water waste from buildings. More importantly though, such inspections may detect and warn about serious safety hazards at some properties. The strong warnings issued below intend to reduce septic system safety hazards for inspectors and property owners/occupants, but it is not the author's intention to dissuade inspectors from providing this valuable service. But danger lurks at cesspools, open covers, tanks or tank covers in poor condition, and from high levels of methane gas. These risk collapse, falling, asphyxiation, and other potentially fatal hazards as well as risks of unsanitary conditions.

• Don't work alone: Falling into a septic tank or even leaning over a septic tank can be fatal. Do not work on or at septic tanks alone - workers can become suddenly overcome by methane gas.
• Do not ever go into a septic tank unless you are specially trained and are wearing the special equipment and gear for that purpose, including self-contained breathing apparatus.
• Don't enter the septic tank: Never go into a septic tank to retrieve someone who has fallen in and was overcome by toxic gases without a self-contained breathing apparatus (SCBA). if a SCBA is not available, call for emergency services and put a fan at the top of the tank to blow in fresh air.
• Don't lean over the septic tank openings Do not lean over or stick your head into the septic tank to examine its interior - you could fall in to the tank or become overcome by gases and fall into the tank, an event which is likely to be fatal.
• Don't ignite flames Do not light a flame at or near the tank - methane gas is explosive. At one tank pumpout my client described the explosion and burns received by the pumping contractor when he stood by the tank and lit a cigarette.
• Site must be ventilated: Decomposing wastes in the septic tank produce toxic gases (such as methane) which can kill a human in a matter of minutes. When working on a tank be sure the area is well ventilated.
• Rope off & Mark Dangerous Sites: If your inspection discover that there are dangerous conditions, such as an unsafe tank cover, tank collapse, or a home-made septic tank or cesspool (which are at increased risk of sudden collapse) such areas should be roped off and clearly marked as dangerous to prevent access until proper evaluation and repairs can be made.
• Safe covers: be sure that the tank and its access ports have sound and secure covers that do not risk collapse and which cannot be removed by children.
• Septic & Cesspool Collapse Hazards: Old steel tanks, thin, rusting steel or rotting home-made wood tank covers, site-built tanks and cesspools, and recently-pumped cesspools are at particular risk of collapse. Falling into a septic tank or cesspool is likely to lead to rapid asphyxiation from methane and in cases of collapse, there is risk of becoming buried. The author has consulted in cases involving such fatalities (homeowner fell into a site-built cesspool), and at one site inspection, walking near an overgrown area the author himself stepped through a rusting steel septic tank top, surviving only by throwing himself into a nearby clump of brambles! Beware of
  • flimsy, rusted, old-steel, home-made, or missing septic tank/drywell/cesspool covers
  • abandoned systems which may not have been filled-in
  • collapsed, or collapsing septic tanks or cesspools
  • possible presence of multiple components at a property, abandoned or in-use
• Unsanitary conditions: Be alert for unsanitary conditions such as surface effluent or sewage backups into buildings, events which risk serious viral and bacterial hazards and which indoors, may require professional cleaning. Be alert for personal sanitation hazards when working around septic systems, such as open cuts or failure to wash properly after working on systems.
• Damage to Septic Components: Avoid damaging septic system components or the building: Improper septic testing procedures, such as flooding a dosing-system, can damage the system. Also, remember to check for leaks into or under the building being tested when running water into the building fixtures and drains. Don't leave water running unattended - at risk of flooding the building.

Septic Systems Online Book

Septic System Safety Warnings for Home Owners and Home Buyers

Septic system concerns for a building owner start with safety. Here are some red flags:

• Signs of collapse-possible fatal hazards: include depressions or "soil subsidence" anywhere on or around the property. Any suspect area should be roped-off and absolutely no one should walk over or even close to such a spot until it has been investigated by a professional.
• Old or abandoned systems: such as site-built cesspools or drywells were often made with a thin steel or wood cover which with age can collapse. If the history of the site or visual observation suggests that there are or were old systems at the property, professional investigation is warranted. Improper "abandonment" (failing to fill-in a pit) can lead to sudden collapses. Signs that there may be old systems at a property might come from anecdotal evidence (ask a neighbor, ask the local septic installing or service companies), or visual evidence such as seeing abandoned waste pipes at basement or crawl space walls or floors. Don't assume that an old house which is now connected to the public sewer didn't previously have an on-site waste disposal system.
• Septic service by untrained workers: such as aerating, agitating, or pumping out an old site-built cesspool, can lead to sudden system collapse. Prevent access over or near any such systems.
• Unsanitary conditions such as discharge of sewage effluent to the yard surface, to a nearby well or stream, or previous septic backups into a building deserve professional attention. Indoors special cleaning may be needed to remove bacteria or other pathogens.
• Septic testing by inexpert "inspectors" who may not follow an adequate procedure increases the risk of a costly surprise.
• Uninformed homeowners may not notice a danger or malfunction .Homeowners should review the safety warnings listed above. The information here is general in nature. Since conditions and requirements vary widely at individual sites, the you should obtain qualified expert advice pertaining to the specific system about which you have questions, and should not rely on this general text for costly diagnostic/repair/replacement decisions. In other words, I'll try to give you some helpful information. In exchange, don't expect me to pay for your new septic system.

Septic Systems Online Book

Septic Inspector Qualifications/Licensing

If you perform septic inspections you are obligated to do so with proper information, training, procedures, and in some communities a license is required. Some states (e.g. CA, CT, NJ, MA) have specific certification requirements for inspectors of septic systems, as well as specific regulations regarding the performance of the inspection itself. Be sure to obtain information pertinent to your own state, usually from the state health department or state department of environmental protection. For example, Massachusetts septic inspectors will want to look at the links and the Title 5 regulations at our page on the Massachusetts Septic Testing Law. Other links to septic system installation and inspection regulatory agencies are at our "Local, State, U.S. Federal Government, & International Agencies & Resources for Septic Systems Wastewater Treatment" page.

Septic System Inspection Authorities

INSPECTION AUTHORITY: some municipalities and states (EG. Pennsylvania) provide septic inspection and testing certification. However a generalist inspector such as an ASHI professional, in the course of a home inspection, is permitted to observe and report visual evidence of defects, probable, or possible defects, just as any contractor might observe and report when coming to a property for any reason.

For municipalities requiring certification of septic test providers, home inspectors should consult with local officials for further advice.Note: some authorities, such as New Jersey Administrative Code 7:9-3.17 (b)5 require septic system evaluations to be performed only by a licensed professional engineer, licensed health officer, licensed sanitary engineer, or trained technician under supervision of the septic system inspector as defined in the pertinent code.

However our review of these codes finds them probably unenforceable since in some instances the codes contradict themselves (see quote below) or the code agencies provide homeowner pamphlets calling for annual inspections which are made by the homeowner him or her self. "All testing of operating systems which requires a hydraulic loading which is in excess of the design flow shall be performed under the supervision of a licensed professional engineer." (New Jersey EPA, Sub 12, 7:9A-12.7 System Testing.") Some codes also require that the details of the septic evaluation procedure itself be included in the report. [Information courtesy of Ed Fitzgerald, ASHI.]

The next chapters discuss ways in which septic system components fail, and with the inspection of the individual septic system components.

Septic Systems Online Book

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FAILURE CAUSES - Septic Failure Causes: How Does Each Septic System Component Fail? - What to Look For During a Septic Inspection

This chapter is maintained at Septic Failure Causes: How Does Each Septic System Component Fail? - What to Look For During a Septic Inspection, but text is repeated here for readers who scroll down rather than linking to the separate chapter.

This chapter discusses detailed "how to" steps instructing the investigator in how to inspect specific septic components for signs of failure. The following section will discuss types and causes of septic failure and will provide criteria that define "failure."

Before digging up your septic tank or calling a septic pumper, if you think the septic system is failed because of drain blockage or drains backing up into the building, you should to see "Diagnosing Clogged Drains: Is it a blocked drain or the septic system? - A First Step for Homeowners". If you link to that text, please return here using your browser's "BACK" button.

Onsite Waste Disposal System Failure Criteria

Massachusetts Title 5 lists specific failure criteria and serves as a good model for septic inspections anywhere.

• Backup anywhere in the system
• Discharge of effluent to the surface, stream, etc. regardless of whether or not septic dye is observed
• Static effluent level or floating scum over the top of the baffles in the septic tank [added by DF]
• Static effluent level above outlet in the D-box
• System has to be pumped more than 4x/year
• Metal septic tanks (municipality dependent; note that in special site conditions small metal tanks may be the "only" solution and may be approved by local officials. An owner/buyer must be informed of the implications of such installations.)
• Soil Absorption System (or cesspool, etc) is at a depth exposing it to the maximum groundwater level

Septic Systems Online Book

Inspecting Outside Waste Piping

Outside waste piping conducts sewage (black water and gray water) from the building to the treatment tank or "septic tank," and from the treatment tank to the distribution box. These lines should be of solid, non-perforated material and need to be protected from mechanical damage (such as by vehicles). Piping extending from the distribution box into drain fields is normally perforated, though solid lines might be used if effluent is being processed by more specialized devices such as seepage pits, galleys, or a sand-bed system.

House to tank

This line may become blocked by waste, damaged by collapse of a section, or invaded by roots. Detection of these conditions is fairly easy by routing a snake or power snake from the building drain to the septic tank. An experienced power snake operator can often tell by "feel" that a drain line is collapsed, partially collapsed, or invaded by roots. While you may make a temporary "repair" of such a condition by drain-cleaning, if the line is broken or root-invaded, you should expect to have to excavate and replace it soon.

Tank to Distribution Box

The same failures can occur on this line as from house to tank. Opening the D-box can also show whether or not effluent is being directed uniformly into each of the leach lines. A tipped D-box can overload one line and cause early failure of the absorption system. If this is happening, flow adjustment end-caps (eccentric holes) can be installed in the distribution box on the inlet end of each of the drain lines, permitting adjustment of effluent delivery into each line, perhaps relieving the problem line and redistributing effluent into the others.

Drain field piping

In a conventional "drain field" of perforated pipes buried in gravel-filled trenches, a drain line may be invaded by tree roots. This is why experts advise keeping tree and shrub plantings away from drain fields. Vehicle traffic can also collapse this or any outdoor waste piping, which is why experts advise against ever driving over a drainfield or over any other septic system components.

Septic Systems Online Book

INSPECTING TANKS - Inspecting Septic Tank Condition

This chapter is maintained at Septic Tank Condition - How to Inspect Septic Tanks but text is repeated here for readers who scroll down rather than linking to the separate chapter.

The purpose of the treatment tank or "septic tank" is to contain solid waste and to permit the beginning of bacterial action to process sewage into a combination of clarified effluent, settled sludge, or floating scum in the tank. An intact, un-damaged septic tank is normally always filled with these materials. However the inspector performing a "visual" check of the septic system needs to be alert for some important findings:

• Subsidence at the tank location - may risk dangerous, potentially fatal collapse
• Evidence of recent work
• Evidence of backup or effluent breakout at the surface in the tank area

Only by pumping and visual inspection can actual tank capacity and condition be completely determined. Probing in the area of a tank, without excavation, is not recommended as the probe may damage a steel or fiberglass tank. When a tank is uncovered for pumping additional critical details may be observed before the pumping operation

• Condition and safety of the tank and access covers
• Liquid and waste level in the tank - evidence of waste passing over the baffles - a flooded system, an indicator of system failure
• damage to the tank baffles

When the tank is opened and to be cleaned or pumped out additional information is available:

• Thickness of scum and sludge levels: Septic tank maximum scum and sludge buildup prior to pump out, and instructions for measuring the floating scum layer thickness and settled sludge layer thickness in a septic tank are available in a separate chapter at Septic Tank Pumping Guide
• Back-flow of effluent into the tank during pumpdown - an indicator of flooded leach fields
• Additional evidence of damage to the tank baffles
• Evidence of damage to the tank itself - cracks, leaks

Septic Systems Online Book

Steel septic tanks

Steel tanks typically last 20-25 years, then rust, and collapse. Before this time steel baffles may rust off (damaging the drain field with sludge) or the tank top may become rusty and unsafe. Since steel tank tops can be replaced while leaving the old tank in place, the condition of the top itself is not a reliable indicator of tank condition.

Rusting steel tank covers can cause death! Rusted covers can collapse. I have reports of children and adults who have died from this hazard, as recently as December 1997. In 2000 I consulted in a fatality involving an adult falling into a cesspool. At a building inspection I myself stepped through a hidden, rusted-through steel septic tank cover. Falling into a septic tank, drywell, or cesspool is quickly fatal, either from being buried by falling soils and debris, or by asphyxiation. Septic gases are highly toxic and can kill in just minutes of exposure. Even leaning over an empty (just pumped) tank has led to collapse and fatality of a septic pumper.

Steel tank baffles: rust out and fall off, permitting solids to enter the soil absorption system

Steel tank bottoms rust out permitting effluent to leak into soils around the tank, possibly giving a large void in tank at time of testing, thus subverting a loading or dye test.

Concrete septic tanks

Concrete tanks at an existing septic installation are usually viable, but might have damaged baffles or cracks that permit seepage of groundwater in or septic effluent out around the tank. Occasionally we've seen tanks made of poor-quality concrete (insufficient portland cement) which eroded badly. If the tank outlet or absorption system have been blocked, examination of the tank interior may show that effluent is or has been above the top of the baffles (see "baffles" below) thus indicating a system failure discussed next.

Concrete tanks can crack or sections may separate causing leaks with the result of not only improper disposal of effluent (wrong location) but also subverting an attempt at a septic loading and dye test since when the system is un-used the tank liquid levels drop abnormally. The inspector may detect this condition only if there is a tank inspection port which is readily and safely accessible for before, during, and after inspection when running a loading and dye test.

Septic Systems Online Book

Home made or "site built tanks- [TBD]

Site built systems, in my experience, are often under-sized and worse, dangerous. There is a serious risk of collapse of old rotting wood covers, collapsing concrete block dry-laid tank or "cesspool" walls, etc. Other types of tanks and home-made onsite systems are described below at Septic Tank Type, Capacity, Material Details

Baffles: Inspecting the Condition of Septic Tank Baffles

Baffles in a septic tank are provided to keep solids and floating scum and grease inside the tank. Baffles are provided at both the inlet to the tank (from the building) and the outlet from the tank (to the absorption system).

Broken baffles or high sludge levels can cause solids to flow out of the tank and into the absorption system. The result is reduced absorption into surrounding soil and eventual failure of the system. Floating scum thickness and settled solids thickness can be measured through access ports into the tank or cesspool. Finding solids at or covering the outlets or damaged baffles should result in report of a very questionable adsorption system and possible major repair cost.

Concrete tank baffles: may erode from chemicals, detergents, poor concrete mix, water flowing over top of baffles, or may be broken by improper pumping procedures

If baffles are lost or damaged (rusted off on a steel tank or broken off on a concrete tank), they can be repaired or replaced. For example at a steel tank the contractor may simply insert a plastic piping "Tee" into the tank inlet or outlet to create a new baffle system.

However, depending on how long the tank was used without good baffles, the volume of solids and grease that moved from the tank to the absorption system will have begun clogging soils there and will have reduced the future life expectancy of the absorption system.

Baffle damage and repair, or even a complete tank replacement when the absorption system has been left alone always lead the author to warn the building owner that the future life of the absorption system may be in doubt and that additional expense will be involved.

Septic Systems Online Book

Solids: Inspecting the Level of Accumulated Solids, Sludge and Floating Scum in Treatment Tanks

Solids entering a septic tank are intended to remain there until pumped out during tank service. A large portion of solids settle to the bottom of the tank as sludge. Grease and floating scum remain at the top of the sewage in the tank. Baffles (discussed above) help keep solids, scum, and grease in the tank. Bacterial action in the tank make a modest reduction in the solids volume and begin the processing of sewage pathogens, a step later completed by soil bacteria in the absorption fields.

Net free area: If the sludge level becomes too high or the floating scum layer too thick, in addition to risking passage of solids out of the tank (damaging the absorption system), the remaining "net free area" of liquid in the tank is reduced. When the net free area becomes too small, there is insufficient time for waste entering the tank to settle out as bottom sludge or top floating scum. That is, for an in-use septic tank with a small net free area, the frequent entry of solid and liquid waste will keep the tank debris agitated, thus forcing floating debris into the absorption system where the life of that component will be reduced (due to soil clogging).

The importance of keeping an adequate net free area in a septic tank is the reason that tanks need to be pumped at regular intervals. Building owners who never pump a tank until it is clogged have already damaged the absorption system.

Septic Systems Online Book

Measuring septic tank sludge thickness & scum layer

Septic tank maximum scum and sludge buildup prior to pump out, and instructions for measuring the floating scum layer thickness and settled sludge layer thickness in a septic tank are available in a separate chapter at Septic Tank Pumping Guide: When, Why, How to Pump A Septic Tank

Septic Systems Online Book

SEPTIC TANK TIPS - Septic Tank Types, Capacity, Material Details

Septic Tank Types: concrete and steel septic tanks and warnings are discussed above at Inspecting Septic Tank Condition.

Septic Tank Size Requirements and How to Calculate the Size and Volume of a Septic Tank are discussed in a separate chapter, " Table of Required Septic Tank Sizes: Septic Tank Capacity vs Usage in Daily Gallons of Wastewater Flow & How to Calculate the Size (in gallons) of a Septic Tank"

Other septic tank types: might include site-built cesspool using concrete blocks or rubble, steel drums, or other. Beware of very limited capacity, failure to comply with local codes, etc. Steel tanks are at high risk of rust and collapse, and higher risk of loss of baffles; frequently tank cover is damaged by excavation for pumping if no cleanout opening is provided.

Limited Capacity of site-built equipment: Homemade systems are very likely to be in violation of local plumbing codes and standards; significant costs to cure may be involved. Tanks smaller than 900 gallons are below minimum size in some jurisdictions. Areas of wet soils, or very small yards should suggest that there may not be room for a conventional absorption system.

Extra costs will be involved in repairing or extending such installations. Sand-bed filtration systems may have to be replaced with other more costly systems when their operation fails or a use permit expires. Systems that dump into local waterways may require periodic inspection and re-certification by state departments of environmental conservation, or may be outlawed. Use of "drywells" to separate graywater from sewage may be clues of limited system capacity. Graywater may not be discharged to the surface nor to storm sewers.

More Reading:
Septic Tank Pumping Guide which gives the tank pumping schedule as a function of tank size and wastewater usage (or occupants).
Septic System Additives & Chemicals and advice about using them to "help" or "inoculate" or "fix" your septic system.

Septic Systems Online Book

INSPECTING THE D-BOX - Inspecting the Septic System Distribution Box

This chapter is maintained at INSPECTING the D-BOX but text is repeated here for readers who scroll down rather than linking to the separate chapter.

The distribution box (more than one may be in use) connects a single effluent line from the septic tank to a network of absorption system components such as drainfield leach lines or to a network of seepage pits or galleys. The photo above shows the adjustable weir outlets that permit balancing flow among drainfield lines. (Source EPA who used photo from Ayres Associates.) More sketches of D-box layouts and configurations are shown in this EPA drawing.

Regulating effluent distribution: In good system design the outlet openings from the distribution box to each drainfield line can be adjusted to regulate the flow among the various absorption lines. Elegantly simple, a plug with an eccentric hole is inserted into the end of each leach line fed from the D-box. By turning the plug in the end of the leach line pipe one can place the eccentric hole higher or lower with respect to the bottom of the distribution box, thus compensating for a slightly tipped box, differences in leach line length, or differences in leach line condition.

Uneven effluent distribution: If a distribution box becomes tipped (or clogged) effluent may be routed to only a portion of the absorption system, thus overloading it and leading to a "breakout" of effluent at the surface or to clogging and system backup. An examination of the box interior may show flood lines in the box if the drain field has been clogged or saturated in the past even if at the time of inspection the box is not flooded.

If the fields have been flooded you should be pessimistic about the remaining life of the absorption system. If the box is tipped and/or effluent has not been uniformly distributed among the drainfield lines (assuming they are of equal length and in equally good soils), only a simple adjustment of the outflow may be needed. Round plugs with eccentric openings may be present or can be inserted in the D-box outlet openings to regulate flow among the individual absorption lines. (C)Trap Daniel Friedman Copyright Protected text.

Tipped or flooded distribution boxes, resulting in uneven loading of soil absorption system lines. This condition can flood one or two lines leading to early field failure.

The Septic Systems Online Book - Where Are We?

INSPECTING FIELDS - Inspecting the Absorption System or Drainfield

This chapter is maintained at SEPTIC FIELD INSPECTION - Septic Failure Causes: How Does Each Septic System Component Fail? - What to Look For During a Septic Inspection. Text is repeated here for readers who scroll down rather than linking to the separate chapter.

This chapter discusses types of septic system failure in the drain field, leach field, seepage bed, or similar component. We list the causes of each type of septic component failure, and list the septic component failure criteria or in other words what conditions are defined as "failure"?. The detailed "how to" steps instructing how to inspect specific septic components for signs of failure are discussed in the text above.

Absorption Field Failure Causes of drainfields and leaching beds

• Soil clogging at the biomat layer which forms below and around the drainfield trenches (or other absorption systems). The biomat is a bacteria layer which forms in soil below and around drainfield trenches where septic effluent or wastewater is discharged. This layer is critical in the processing of fine biological solids and pathogens which are in the effluent, and without it the septic system would not be adequately treating the effluent. Inadequately-treated effluent released into the ground risks contamination of nearby ponds, wells, streams, etc.
• Driving over the absorption system, leach field, drainfield
• Paving over the absorption system
• Flooding the absorption system with surface or roof runoff, or rocky, poorly-drained or under-sized sites may simply lack capacity
• Use of septic tank or drain field additives which claim to extend system life can generate so much activity in the tank that solids are held in suspension and forced into the soil absorption system! Do not add any treatments, chemicals, yeast, or other treats to a septic system. In general these treatments don't work, may ruin the system, and are illegal in many localities. There is no magic bullet to repair a bad SAS.
• Improper original construction , especially on rocky, poorly-drained sites (pipes settle, for example)
• Houses clustered around a lake: often will have a marginal system as properties were crowded together, built as part-time summer-camps, were built without code supervision, and often were built using amateur, marginal home-made systems.
• Age: eventually even a well-maintained SAS will clog and have to be replaced.

More Reading:
The formation, clogging, and measures to protect and extend the life of the biomat is discussed at Septic System Absorption System Biomat Formation as a subchapter of this text.

Septic Systems Online Book

DISPOSAL vs TREATMENT - Effluent Disposal and Drain Clogging Failures

In simplest terms, there are two visible septic effluent or onsite wastewater disposal failures:

• Toilets or other fixtures back up into the house - but first see "Diagnosing Clogged Drains then return here using your browser's "BACK" button.
• Effluent or sewage appears at the surface of the yard, or the neighbor's yard!

Septic odors may also indicate a system failure or an imminent failure. But such odors may also be produced by defects in the plumbing vent system or other site conditions. Beware, sewer gas contains methane and is explosive if it reaches a dangerous concentration inside a building.

Typical causes range from things that are easy and cheap to repair, to a need for complete system replacement:

• Clogged pipes
• Broken pipes
• Damaged tank
• Tipped distribution box
• Clogged/broken soil absorption piping
• Clogged absorption soils (grease & solids)
• Saturated soil absorption area

However there can also be septic effluent treatment failures. Effluent may not back up or appear on the surface, but if insufficiently treated effluent reaches a private well or any stream or waterway, the environment is being contaminated -- an unacceptable condition. Historically many people have just worried about disposal. As the quality of drinking water deteriorates in many areas and as population grows in many previously thinly-populated areas, proper treatment has become the real concern for everyone's health.

For example, if there is not sufficient soil between the bottom of the soil absorption system trenches and the local groundwater, the local environment is being contaminated.

SEPTIC FIELD FAILURE CRITERIA - Soil Absorption System Failures: (leach fields, drain fields, seepage pits)

Drainfield life: What destroys or shortens the life of the absorption system?

It's easy to ruin or shorten the life of a drainfield/leaching bed:

• install a drainfield in wet weather (which compacts the soil)
• drive over the drainfield or build a parking lot over it (compacts soil, breaks pipes)
• plant trees on the septic absorption field (roots enter pipes)
• put a swimming pool in the middle of a drainfield - yes I've seen people do this!
• forget to pump out the septic tank regularly (solids/grease are discharged into the fields, clogging the soil)
• direct roof runoff or surface runoff across the drainfield or into the septic tank (flooding the system)
• install the drainfield in an area of high seasonal water tables (flooding the system)
• use the septic system to dispose of illegal oils, chemicals, fats, greases - one system in New York near the Taconic State Parkway was connected to house in which was operated an illegal drug manufacturing operation. So much contaminant was flushed down house drains that the workers contaminated their own well and poisoned themselves
• discharge excessive salts or other chemicals which destroy the The formation, clogging, and measures to protect and extend the life of the biomat is discussed at biomat in the drainfield

Soil Absorption System Failure Criteria

• Breakout of effluent observed (& I consider odors as well)
• BOH evaluation in MA if within 100 ft of surface water supply
• within Zone 1 of a public well
• within 50ft of a private well
• between 50ft and 100ft of a private well if well fails bacteria test.

Septic Systems Online Book

The Drainfield: Leaching Bed Soil Condition & Liquid level

The absorption system or "drain field" has two jobs. First, it disposes of liquid effluent by permitting it to seep into the soil below. Second, a "bio-mat" of bacteria which forms in the soil below the drainage field processes pathogens in the septic effluent to make the effluent sufficiently sanitary as to avoid contaminating nearby ground water.

This distinction between successful "disposal" and successful "treatment" is important to avoid groundwater contamination but has not been addressed by regulation in every municipality. Municipalities which require a minimum distance between the bottom of the drain field trenches (or equivalent component) and the top of the seasonal high ground water table have recognized the importance of a working bio-mat and the need to provide adequate dry soil for it to function.

Even in a well-designed drainage field, eventually the soil surrounding the drainfield device (perforated pipe in gravel trench or other seepage system) becomes clogged with grease and debris. Examining an excavated cross-section of a failed drainfield will often display a black or gray band of sludge and grease of about 1" thickness at the inside perimeter of the gravel trench. When this layer of soil becomes sufficiently clogged the passage of effluent into the soil below is slowed and eventually blocked, leading to the need for replacement. Keeping a tank pumped so as to reduce the passage of debris and grease into a drain field will extend its life.

This is the most expensive problem to correct. Look for septic effluent seepage to ground surface in area of equipment or downhill from such equipment. Look for (illegal) drain field line extensions to nearby streams, storm drains, or adjoining properties where the temptation to "fix" a failing system by sending the effluent to an improper destination overwhelmed a previous owner or repair company. In some areas inspectors use septic loading and dye test. Seepage may be due to overloaded tank, failed absorption system, or blocked/broken piping (may be less costly).

An excavator or septic contractor will often explore one or more drain lines (or similar components) by excavating a portion of it to look for evidence of flooding or soil clogging. We've used a simple probe at the end and along a leach bed to check for flooding of that component. (Be careful not to break or collapse old piping.)

Septic Systems Online Book

Guide to Septic Drainfield PERC TESTS - Septic Soil Percolation Requirements and Soil Depth Requirements for Septic Absorption Systems / Septic System Drainfields

This chapter is maintained at Soil Percolation Requirements and Soil Depth Requirements for Septic Absorption Systems / Septic System Drainfields but text is repeated here for readers who scroll down rather than linking to the separate chapter.

Perc Tests: What is a septic system soil percolation test?

In specifying the size and type of absorption field (leach field, seepage pits, galleys, other) a septic engineer or health department official will require that a soil percolation test or "perc" test be performed. You may hear it described as a "deep hole test." The first time I participated in this procedure I found myself smiling with surprise at how low-tech the procedure actually was (in New York State.) After identifying the most-likely location on the lot for placement of a septic drainfield, the excavator used a backhoe to dig a rough hole about 5 ft. deep. Happily no groundwater immediately filled in the hole (which would have been bad news).

Perhaps this is why builders try to have this test done in July which is the period of most-dry weather and lowest groundwater table levels. After digging this rough hole, the septic engineer poured a 5-gallon (joint compound) bucket of water into the hole. In some cases a few buckets might be dumped therein.

After that sophisticated move, the observers simply watched the rate at which the water disappeared. a one-inch drop in water level in this hole in three minutes was considered very good. If the water was found still in the hole at no drop in level the next morning, this was considered seriously bad and probably requiring some soil exchange or other special design measures.

What are the soil perc standards> and other soil requirements for septic systems?

I like the Massachusetts Title 5 Septic Inspection criteria for defining a (at least possibly) functional drainfield, as the text explains the role of the biomass below the absorption bed, sets soil depth requirements, and recognizes the importance of keeping the bottom of the working biomass area in well drained soil sufficiently above the seasonal high water table.

Here is an example of soil requirements for a functional drainfield. This version is particularly clearly written and is for residents of Ohio but the principles apply anywhere. "In Ohio, soil absorption systems can be used in areas where the percolation rate of the soil is between 3 and 60 minutes per inch (soil permeability between 1 and 20 inches per hour).

At least 4 feet of suitable soil is required under the soil absorption system to provide adequate treatment of the septic tank effluent. To accommodate the construction of the system and provide adequate soil cover to grade, a minimum of 5 1/2 to 6 1/2 feet of suitable soil is needed above the limiting layer.

A limiting layer may be bedrock, an impervious soil layer (hardpan, fragipan) or a seasonally high water table (gray soil or mottles). The soil absorption system must be at least 8 feet from any drain line on the lot, 50 feet from a water supply, and 10 feet from the property line, right-of-ways and the house. Septic systems cannot be placed on the flood plain and are limited to areas with less than a 15 percent slope." http://ohioline.osu.edu/aex-fact/0743.html Ohio State University Fact Sheet "Septic Tank - Soil Absorption Systems"

Our separate article by Lockwood includes a description of the calculations to answer the question: How Big Should the Leach Field Be? and includes a practical example using sample calculations and a table of soil percolation rate vs. field size

Septic Systems Online Book

FIELD SIZE - Septic Leach Field or Septic Absorption Field Size: How large does the absorption field need to be?

This chapter is maintained in complete form at SEPTIC DRAINFIELD SIZE.

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The size of the absorption field needed (in square feet of area, presumably also unencumbered by trees, driveways, buildings, etc.) can range considerably depending on the soil percolation rate. A lot with a good percolation rate or "perc" of perhaps one inch of percolation in three minutes might require about 4500 square feet for a typical three bedroom home. If the same home were built where there was a poor a soil percolation rate of an hour per inch, 9000 square feet or more might be required for the absorption area.

Drainfield size and location also have to take into account local zoning - setback requirements from property borders, setbacks from streams, wetlands, wells, water supply lines, and other encumbrances.

More Reading:
How Big Should the Leach Field Be? includes a practical example using sample calculations and a table of soil percolation rate vs. field size
Design Basics for Septic Systems: Choosing Septic Tank Size, Leach Field Size - basic septic system volume and absorption system design guides.

Drainfield trench/line specifications

In the most common design of drainfield, perforated pipes are buried in gravel-filled trenches to form the drainfield. Pipes are placed across the slope line of sloped property (so that all of the effluent doesn't simply rush down to and leak out at the end of the drain line pipe). While some experts describe the bottom of these trenches as "level" in practice they are dug to slope slightly, perhaps 1/8" per foot or less.

A typical septic leach field trench is 18 to 30 inches in depth, and 8 to 12 inches wide. The trenches are dug about 6 feet apart which allows, in good design, space for a set of replacement trenches to be placed between the original ones when the first set fails. The maximum length of a trench is typically about 150 feet but I've found installations that were three times that length.

Where lot space does not permit drainfield trenches such as I've just described, a septic engineer may specify that seepage pits or galleys are to be installed. These fit in a smaller space since a single pit may be 6' to 8' in diameter. But the depth to which effluent is being delivered (4' or more) means that the sewage effluent is unlikely to be fully treated by a biomass. These systems may successfully "dispose" of effluent but they are probably not adequately "treating" it.

[See Tables for sizing drainfields and mound systems, USDA, soils, guide to Soil percolation tests, trench dimensions, loading in gpd per foot. e.g. , moderately limited perc rate of 5-10 min/inch has max sewage loading rate to trench and bed bottom of 1 gallon per square foot per day per trench and .5 gal per bed.

The Biomat: The formation, clogging, and measures to protect and extend the life of the biomat, or organism layer below and around soil absorption system effluent discharge piping is discussed at Septic System Absorption System Biomat Formation as a subchapter of this text.

Septic Systems Online Book

MOUND SYSTEMS - Septic mound systems

The complete form of this chapter is maintained at MOUND SEPTIC SYSTEMS.

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To build a mound system, extra soil is brought to a site and sculpted to form a drainfield of adequate thickness and area. These systems are common where soils are rocky or where there simply is not enough soil above the local water table to provide adequate absorption.

A mound system may be fed by gravity at some sites but it's also common for the effluent to reach the mound by having been "pumped-up" from a septic tank. Pump-up (to elevations higher than the building main drain exit) and some septic mound systems use a single or duplexed pump either in a clear baffled section of the tank, or in a separate effluent pumping chamber. Duplexed systems offer more reliability. If the first pump fails the second takes over, and an alarm bell or light are turned on. Grinder/Ejector pumps are used at both private and public sewage disposal systems to pump up from low areas (such as a basement toilet) where the sewer line exits the building at a higher level and where gravity drains are therefore not workable. Flush-up toilets, systems that use a venturi-system rather than a grinder pump, may be encountered but may be in violation of local plumbing codes as they may comprise an unsanitary cross- connection (using house water pressure to force sewage up and out).

What ruins a septic mound system?

A good way to ruin a septic mound system or to build one with a short life is very common in the Northeastern U.S. where I find what I call "pseudo mound septic systems" in which the builder has killed two birds with one stone. Instead of clearing an area and bringing in the proper volume and type of soil to build the mound, the builder finds a spot into which s/he can push all of the tree stumps and construction debris from the building project. The stumps and trees are then buried with backfill to produce an nice looking "mound" with just enough soil to bury a network of drainfield pipes. If you see a mound system that has horizontal trees sticking out of its base, or if it has mysterious pipes leaving its base, I would be very suspicious about the design and longevity of the system, as well as concerned about its legality.

Septic Pumps and Alarms for Septic Tanks and Mound Systems

[TBA] Additional data on this topic for Canada: see Ministry of the Environment, Class 4 Sewage Systems, on hand via AC

More Reading about Septic Mounds

SEPTIC MOUND SYSTEMS as Components of Alternative Septic Systems for Difficult Sites
Mound System Installation and Design Details from New York State Septic System Design Regulations 75-A.9 Alternative Septic Systems.
Ohio State University has a nice web page describing Septic Mound Systems.

DRYWELLS - or seepage pits for disposing of gray water onsite

The complete form of this chapter is maintained at DRYWELLS.

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A drywell, or "seepage pit" is used at some building sites to receive "gray water" from a laundry, sink, or shower.

The pit may be site-built of stone or dry-laid concrete block, rubble-filled, or constructed of (safer) pre-cast concrete. Design may be similar to that of a cesspool, described above, but only gray-water and not sewage is discharged into a drywell.

Drywell Warnings

• Safety: the same concerns for collapse hazards apply as were described above for cesspools.
• Limited septic system capacity is implied by the presence of a drywell. Wet soil conditions or limited space for a functioning drain field (for the septic system) often leads property owners to reduce the liquid load on the septic system by routing gray water to a separate drywell. Where such a system is installed owners/buyers should be alert for these conditions and should expect to face extra costs for system maintenance and repair as well as limited septic system capacity.
• An exception to the warning above: at a large building where a sink or laundry are added in an area distant from piping connected to the septic system, an owner may add a remote drywell as an alternative to inconvenient and costly routing of a drain line from the laundry to the existing septic system.

Drywells in many areas are a misnomer since during wet weather as water tables rise, the "drywell" is not very dry and in fact may fill up with water and simply stop working.

In wet areas of the Northeastern U.S., for example, I disagree with the practice of "solving" a roof drainage disposal problem at a flat site by building a "drywell" since in my experience these fail rather soon and in some cases even fill up and work backwards, sending water back to a building footing drain or roof drainage system where water then leaks into the building!

Septic Drywells

Septic Systems Online Book

CESSPOOLS for onsite wastewater disposal

See CESSPOOLS for the complete version of this chapter.

A cesspool combines the septic treatment tank and absorption system into a single component. Basically a cesspool is a stone or concrete block or (safer) pre-cast concrete (photo) lined pit into which sewage is discharged. Solids remain in the pit, effluent is absorbed into soil below and at the sides of the cesspool. This older design was often used where there is limited physical space, and where the soil absorption rate high. We have more to add to this section, but the bottom line is that for most installations you should consider this an obsolete, limited capacity system likely to need replacement, and involving significant cost. Some immediate concerns are stated next.

Cesspool Safety Warnings

• Safety Warning: do not walk over the top of or close to the edges of a cesspool or any other onsite pit or excavation because of the danger of fatal collapse. Keep pets and children away from such systems.
• Safety Warning: there is a high risk of cesspool collapse, risking fatality if someone falls in to one of these systems. This is particularly true for older site-built systems that were often made of dry-stacked stone or concrete block, and more-so if such systems are not protected by a very secure cover.
• Safety Warning: pumping cesspools is dangerous since older site-built systems may be more likely to collapse inwards when relieved of their contents.
• Safety Warning: aerating or agitating sludge at the bottom of a cesspool in an attempt to renew its function or extend its life also risk system collapse.

Cesspool Failure Criteria (MA)

Failure Criteria for Cesspools: If the waste level is within 12" of the inlet pipe near the top of a cesspool the system is at end of life and needs to be replaced. Some municipalities and experts will state other distances. In Massachusetts according to the Massachusetts Title 5 Septic Law the following are considered a failed or unacceptable cesspool installation:

• less than 6inches of freeboard
• less than 1/2 day's storage
• within100 ft. of a pond or dug well (surface water supply)
• within50 ft. of a private well (modern sanitary well)
• between50 and 100 ft from a private well if well fails bacteria test
• inMA, within Zone 1 of a public well
• BOH evaluation is required if within 50ft of any surface water

Septic Systems Online Book

Definitions of Levels 0-1-2-3 of Septic System Inspection and Testing

See SEPTIC INSPECTION TYPES & LEVELS for the complete version of this chapter.

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Anyone inspecting septic systems MUST be familiar with the hazards and safety concerns discussed at SEPTIC SYSTEM SAFETY WARNINGS

Please see SEPTIC INSPECTION TYPES & LEVELS for our complete article on this topic. That article includes these subtopics:

SEPTIC SYSTEMS INSPECTION COURSE
SEPTIC INSPECTION TYPES & LEVELS
  LEVEL-0 SEPTIC INSPECTIONS
  LEVEL-1 SEPTIC INSPECTIONS
  LEVEL-2 SEPTIC INSPECTIONS
  LEVEL-3 SEPTIC INSPECTIONS
SEPTIC INSPECTION WORK SHEETS
SEPTIC TANK INSPECTION PROCEDURE
SEPTIC FIELD INSPECTION
INSPECTING SEPTIC D-BOX
SEPTIC FIELD INSPECTION
SEPTIC DYE TESTS
SEPTIC FAILURE SIGNS
SEPTIC SYSTEM SAFETY WARNINGS

Basic descriptions of these levels of septic testing follow below but full details are in the above articles.

LEVEL-0 Septic Inspections - Basic Visual or Visual Plus Loading & Septic Dye Test - no pumping

This level of inspection is typically provided during a "home inspection" for real estate transactions. It pumping may not be appropriate if the system is a recent installation (less than 2 years old), or if it has been recently pumped (a year or less, perhaps more depending on tank size and building occupancy), and if there are not other historical or site observations raising question about the system condition.

1. VISUAL ONLY: Basic visual inspection and reporting of information (Performed by home inspector or other expert) (Some municipalities require this test be performed only by specifically licensed septic contractors or engineers.)
   
   
2. VISUAL PLUS LOADING DYE TEST - Visual + Dye test and system loading. Warning: using an inadequate amount of tracer dye or an insufficient volume of water for this test will make it meaningless. Therefore ordering a "stand-alone" septic loading and dye test of a system should be expected to cost considerably more than such a test which can be performed overlapped in time with other building inspection services. Beware of quick, minimal tests which place only a small volume of liquid into the system (perhaps 50 gallons over 10 or 15 minutes).

LEVEL 1 Septic Inspections: Level 0 plus open accessible covers, plus Loading/Dye Test, possibly Pumping

This inspection is comprised of:

1. The steps in a Level 0 inspection
2. Additional visual inspection steps to open accessible covers & inspect equipment.
3. Septic Dye Test: This inspection usually include a septic loading and dye test. If a dye test is to be performed it must be done before the system is pumped or further inspected - otherwise the loading test cannot test the absorption system.
4. Pumping: In some states such as Pennsylvania, this level may include requiring tank pump out and inspection. (Performed by home inspector or other expert) (Some municipalities require this test be performed only by specifically licensed septic contractors or engineers.) This is the Pennsylvania PSMA definition for level-1. More detail is at Level 1.

LEVEL 2 Septic Inspections: Level 1 plus scum and sludge levels, pump tank, check D-boxes

This inspection is comprised of:

1. The steps in a Level 0 inspection
2. The steps in a Level 1 inspection
3. Additional steps to:
• locate, excavate if needed, open, inspect the septic tank
• determine the septic system capacity, scum thickness, baffle condition, etc. (Performed by septic pumping contractor or other expert.) (Some municipalities require this test be performed only by specifically licensed septic contractors or engineers.) More detail is at Level 2.
• pump and inspect the emptied septic tank, baffles
• locate, excavated if needed, and inspect the distribution boxes

LEVEL 3 Septic System Inspections Level 2 plus soil and perc tests, poss. engineering analysis

This inspection is comprised of:

1. All of the steps in a Level 0,1, and 2 inspection
2. Additional site excavation to make test openings in leaching area, other test holes to observe soil conditions, test the soil percolation rate, and if needed, perform other engineering work necessary to certify an existing system or to permit specification of system replacement. (Performed by septic pumping contractor, engineer, or other expert.) (Some municipalities require this test be performed only by specifically licensed septic contractors or engineers.)

How to Perform a Septic Loading & Dye Test

The septic loading and dye test procedure, data to be recorded, and minimum quantities of water and septic dye needed are discussed in a separate chapter at Septic Loading and Dye Test Procedure Details - a chapter of this text "Inspecting, Testing, & Maintaining Residential Septic Systems".

Septic Dye Test Warnings to be Included With Septic Test Reports

1. If property has been vacant more than a week or the system has been only minimally used, additional levels of testing and inspection are necessary to determine system condition. If the system has been serviced recently, contact the septic pumping company to inquire about the type and condition of the waste disposal equipment. If the system has not been serviced recently, limited but important additional information regarding the condition of the system may be obtained by having a septic contractor open, clean, and inspect the septic tank (and distribution boxes). Particularly in the case of older systems that have not been serviced, if the property owner will permit this step we recommend it. Excavation and pumping are beyond the scope of our loading and dye-test procedure. Practices in some states require pumping and inspection at sale.
2. Septic systems are basically a "buried" installation which is hidden from normal visual inspection. Many possible problems may not show themselves at the time of a visual inspection, and thus one cannot make accurate prediction of the future condition of the system. Determination of location, condition, or life expectancy of buried septic components is not possible from a visual inspection. Costly problems may not be visible.
3. Periodic pumping is recommended to prevent costly damage to the absorption system. Pumping frequency depends on system usage, tank size, and other factors.
4. The inspection includes visual examination of probable tank and absorption system areas, surface and perimeter, at the beginning, during, and at the end of a loading or dye test, if such was ordered and performed.

The Septic Systems Online Book - Where Are We?

• This Chapter: SEPTIC INSPECTIONS Levels0-1-2-3Next Chapter: SEPTIC FAILURE CAUSES
• First Chapter: SEPTIC SYSTEMS ONLINE BOOK

SEPTIC CLEARANCES - Online Table of Required Clearances: Distances Between Septic System & Wells, Streams, Trees, etc.

This chapter is maintained at Online Table of Required Septic Clearances: Distances Between Septic System & Wells, Streams, Trees, etc. but text is repeated here for readers who scroll down rather than linking to the separate chapter.

Common guidelines are at least 50' clearance or distance between the well and the septic system tank or 150' between the well and the septic drainfield or leaching bed. Beware that local soil and rock conditions can make these "rules of thumb" very unreliable. See "One and Two Family Dwelling Code, Section P-2510-Combined Seepage Pits and Disposal Fields," and Table P-2504, "Location of Sewage Disposal System." Other references are cited at the end of this table.

Typical clearances for septic tank, soil absorption system (SAS), etc. This table describes distance requirements between septic components and wells, streams, trees, property boundaries, lakes, etc. A second section of the table gives distances from wells to septic systems and other encumbrances. NOTE: these distances are for conventional onsite waste disposal systems which specify clearances presuming that effluent is being disposed-of after minimal treatment such as is received by a septic tank or cesspool. Advanced onsite wastewater treatment systems, such as those described by Jantrania and Gross (2006), permit substantial reduction in these clearances, depending on the level of treatment achieved.

More Reading:
Alternative & Advanced Designs for Septic Systems for discussion and links to (on-site waste disposal) System Designs for Problem Sites & Soils. Books, Consultants, Engineers, Designers

TABLE NOTES:
Distances are in feet unless otherwise stated
SAS = Soil Absorption System - Leach Field etc.
Mass.Title5 = Massachusetts Title 5 Septic Code
FL = Florida
NY = New York State
UPC = Uniform Plumbing Code
-1 Distance from source of pollution - proposed construction, US Dept. of Housing and Urban Development, FHA, Local acceptable standard No. 3, June 18, 1992, Ref. Hud Handbook 4910.1 Chg 1, Appendix K, Pg K-27
EPA references above and for other EPA information see Well Construction and Maintenance [Details to Help Avoid Well Water Contamination] US EPA

Septic Systems Online Book

ALTERNATIVE DESIGNS - Additional Septic System Inspection and Maintenance Chapters under development

In case you scrolled down rather than using links at the left, information about alternative septic designs is maintained in separate chapter files listed below.

• See SEPTIC SYSTEM DESIGN BASICS.
• See SEPTIC DESIGN ALTERNATIVES- Alternative Septic System Designs,


• [TBD: Working document notes: add from on hand, tables for sizing mound systems, USDA, soils, percs, trench dimensions, loading in gpd per foot. E.g. , moderately limited perc rate of 5-10 min/inch has max sewage loading rate to trench and bed bottom of 1 gallon per square foot per day per trench and .5 gal per bed. this chapter is under development.
• [TBD: Working document notes: add from on hand, septic tank abandonment procedures and hazards ... see FLASHI seminar notes] this chapter is under development.
• [TBD:Working document notes: add from on hand, septic tank capacity, average sewage flow gpd vs. minimum effective capacity in gallons ... FLASHI and other refs. Few locales may permit new tanks under 900g].

DEFINITIONS - Definitions: Septic System Components & Terms: Definitions

In case you scrolled down rather than using links at the left, our list of definitions of septic system terms is maintained in a separate chapter Septic System Terms and Definitions

Septic Systems Online Book Contents

FAILURE LAWSUIT - A Defective Septic Inspection and Septic System Failure Litigation Case Study
InspectAPedia^®

SEPTPROB.TXT - Excerpt from DJ Friedman arbitration file

The complete version of this chapter is maintained at SEPTIC FAILURE LAWSUIT.

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Complaint that Septic Test Was Not Properly Performed

[home inspector's name deleted] performed a septic dye test, erred by putting water in laundry sink in the basement; ran 125g water, reported system in satisfactory condition; Buyer later found no proper system installed, had to install a "trans vac" pump up mound system, for $16,000, total damages $28,000. Area reported to be known for poor drainage, making mound system requirement likely.

Approach to Analysis of the Septic System Test Complaint

1. ASHI Standards of Practice (exclude requiring Septic test)
2. Define existing professional standards for performing visual + dye test
3. Claim basic error made: test in laundry sink - no evidence. connects to septic

Assertions Made by the Plaintiff Regarding Inadequate Performance of a Septic Loading and Dye Test - Errors of Omission and Commission

1. Common practice includes visual inspection of yard and interior and plumbing to address the pertinent questions, + dye, volume of water, reinspection for breakout. Pertinent questions include attempting to assure that drain used for test drains into the septic fields.
2. An error can be inferred if dye and loading water volume were not introduced into the proper drains. If this is the case, whether or not the proper volume of water was run is probably moot.
3. It is possible that knowledge of area soil characteristics, age of property, local building conditions and practices, might have served as a basis for caution or warning, regardless of whether or not dye was found at the surface. Such warnings are at the discretion of the inspector.

Questions In Determination of Adequacy of Septic Test Performed

1. Is there visual evidence in basement of the subject property that the laundry sink does not or might not drain to same location as main house sewer line? [Yes-arrangement of piping; height of exit of septic drain above sink]
2. Does client recall and can testify that dye was introduced only in drywell? How much water was run? Over what time? (125 g in 1/2hr is about 4.2 gpm which is possible from a reasonably strong flow at a single sink faucet. Typically 3-4 gpm for a kitchen sink, or single tub, depending on pump pressure switch settings, control valve settings, clogged piping, type of pump, etc.) What type of well and pump equipment are provided? Shallow well, deep well, submersible pump vs 2-line jet pump? At what pressure does the pump cut in and out, what type of holding tank is installed, what is the average water pressure in the house, what is the measured flow in gpm from the faucet used to perform the test? only. 125 gals in 1/2 hr is possible and reasonable, but a bit less than the usual volume of water run for septic tests.
3. Would a conventional and properly conducted test absolutely, probably, possibly have revealed a failed system?
• what conditions led to discovery of failure (number of occupants, level of usage, time until failure noted after initial occupancy)?
• exactly what equipment was discovered when the old system was excavated?
• can one reliably infer from what was discovered that question 3 is pertinent and that q3 can be answered?

Court Hearing Notes regarding inadequate septic testing complaint

1. Water was run into laundry drain, nowhere near and no visible connection to main house drain; photo details strongly suggest laundry drain does not or may not drain to septic - wrong place to test. No dye was used.
2. Septic report indicates dye was used etc - in boilerplate. Minimal info. provided by report
3. Home inspection report - a checklist form - completely blank plumbing section - suspect inspector was distracted by something and just forgot this topic - does not meet ASHI standards for plumbing inspection.
4. Septic failed immediately on occupancy - probably less than 200g water run.
5. Subsequent discovery on excavation indicates no functioning septic - sludged tank, no leach lines except. one pipe, completely root-filled. Strong possibility that a proper loading and dye test would have failed;

Results from arbitrator hearing case of improper performance of a septic test

7/3/95 Note to File: arbitrator found for the plaintiff in full, holding that a proper test was not performed and protection contracted-for was not provided.

Septic Systems Online Book

References: Septic System, On-site Waste Disposal Inspection, Maintenance, Testing, Repair, Design: Septic References

The complete set of septic system inspection, testing, design, and repair references is maintained at SEPTIC REFERENCES.

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• We discuss the requirements for different levels of inspections (level 0, 1, 2 septic inspections) at: Septic System Inspection Types & Inspection Levels
• Field worksheets for various types of septic system inspections can be found at Checklists for Inspecting, Testing, & Maintaining Residential Septic Systems
• See Septic Tank Inspection Procedure for details of inspecting septic tanks themselves and a septic tank inspection checklist.
• See Septic Field Inspection Procedure for details of inspecting septic drainfields.
• See Septic Loading and Dye Test Procedure for the details of that process
• See Septic Inspection Testing for our full list of septic inspection methods and procedures.
• See Signs of Septic System Failure: A First Step in Septic Diagnosis, for septic system failure criteria
• See our online septic system inspection course at Inspecting Onsite Waste Disposal Systems - Septic System Testing Methods & Procedures - a Classroom Presentation
• See Inspecting, Testing, & Maintaining & Designing Residential Septic Systems - for our Septic Systems Online Book on this topic

1. "EPA Design Manual: Onsite Wastewater Treatment and Disposal Systems," R. Otis et al, EPA 625/1-80-012. GPO Bookstore, 26 Federal Plaza, Room 110, New York NY 10278 212-264-3825.
2. "Septic Systems," T. & A. Ferrero, Tri State ASHI Seminar, November 6-7 1993, and attachments listed below.
3. "Septic Tank Pumping," Paul D. Robillard, Kelli S. Martin, Penn State College of Agriculture, Cooperative Extension, Agricultural Engineering Fact Sheet SW-161, Agricultural Engineering Department, 246 Agricultural Engineering Building, University Park PA 16802 814-865-7685 814-863-1031 FAX.
4. "Preventing Septic System Failures," Paul D. Robillard, Kelli S. Martin, PennState College of Agriculture, Cooperative Extension, Agricultural Engineering Fact Sheet SW-162.
5. "Mound Systems for Wastewater Treatment," Paul D. Robillard, Kelli S. Martin, Penn State College of Agriculture, Cooperative Extension, Agricultural Engineering Fact Sheet SW-164
6. "Septic Tank Soil Absorption Systems," Paul D. Robillard, Kelli S. Martin, Penn State College of Agriculture, Cooperative Extension, Agricultural Engineering Fact Sheet SW-165
7. "The Soil Media and Percolation Test," Paul D. Robillard, Kelli S. Martin, Penn State College of Agriculture, Cooperative Extension, Agricultural Engineering Fact Sheet SW-163
8. "Level 1 Septic System Inspections During Real Estate Transactions," Paul D. Robillard, Kelli S. Martin, Penn State College of Agriculture, Cooperative Extension, Agricultural Engineering Fact Sheet SW-166
9. "Take Care of Your Septic Tank," Washington State Septic Tank Pumpers Association, (WSSTPA) (Les Eldredge, President, 206-334-8263); Courtesy of Bob Kelwitz, 10/93. Items 3-9 provided courtesy of Jules Falcone.
10. "Cottage Country, Environmental Manual for Cottages," 6th Ed., 1989, ISBN 0-7729-5085-7, Environment Ontario, 135 Clari Ave. West, Suite 100, Toronto Ontario M4V 1P5
11. Septic Tank Maintenance," Circular 1343/January 1990, and "Why Do Septic Systems Fail?," K. Manci & J.A. Moore, Extension Circular 1340/January 1990, Oregon State University Extension Service, and "Know your Septic System," a homebuyer's guide to on-site septic systems, Washington Association of Realtors, Govt. Affairs Dept, PO Box 719, Olympia WA 98507 206-943-3100, provided by Len Sherr, Bend OR
12. One and Two Family Dwelling Code, Section P-2506, Septic Tank Design and Construction.
13. "The Septic Tank Home Wastewater Treatment and Disposal System," Southern Rockingham Regional Planning District Commission, 19 Main St., Salem NH 03079 603-893-5766
14. "Septic Tank News & Views," Stanley Carraway, Florida ASHI Seminar, October 9-10, 1993 available from FLASHI Chapter, includes some USDA tables and charts on design, loading, and references the New (1992) Chapter 10D-6, Florida Administrative Code, Standards for Onsite Sewage Disposal Systems.
15. Pennsylvania Septic Management Association, RD 3 Box 3231, Moscow, PA 18444
16. HUD Handbook 4910.1 (Well Clearances)
17. "Private Sewage Disposal, Some Suggestions," RES-I-TEC, 145D Grassy Plains St., Bethel CT 06801 1989
18. "A Homeowner's Manual for Septic Systems," Robert Berg, Wastewater Facilities Management Element Bureau of Construction and Connection Permits, State of New Jersey Department of Environmental Protection, Division of Water Resources, January 1990, 609-984-4429, courtesy of Lewis Home Inspections
19. "What Remodelers Should Know About Septic Systems,", Russ Lanoie, Journal of Light Construction [New England Builder], July, 1988, p. 31-36, RR#2, PO Box 146, Richmond VT 05477
20. "Water Conservation and Wastewater Disposal," R. Siegrist et al., 1978, ASAE Pub. 5-77:121-136
21. "Soil Infiltration Capacities as affected by septic tank effluent application strategies. In: Proceedings of the 3rd national Symposium on Individual and Small Community Sewage Treatment." ASAE Pub. 1-82 pp. 72-74. ASAE PO Box 410, St.Joseph MI 49085
22. "Aerobic on-site systems studied in New Mexico," Asbury R. and Hendrickson C., 1982, Journal of Environmental Health, 45:86-87
23. "Soil Clogging: Mechanisms and Control," R. Otis, Proceedings of the 4th National Symposium on Individual and Small Community Sewage Treatment, ASAE Pub. 07-85 pp. 238-250, ASAE, 2590 Niles Rd., St. Joseph MI 49085-9659
24. "Residential Graywater Management in California," A. Ingham, 1980. California State Water Resources Control Board, PO Box 100, Sacramento CA 95081
25. "On-site disposal of small wastewater flows," R. Otis, 1977, Department of Civil and Environmental Engineering, University of Wisconsin, Madison.
26. NAHB Library, several resources listed, contact NAHB, 15th and M Streets NW, Washington, DC 20003 202-822-0203. "Pumped septics - improved waste-water systems distribute effluent from septic tanks over a wide area, preventing contamination of drinking water," Noele Stuart, Popular Science, My 1989, p. 84; "Septic tank effluent pump systems: an alternative to conventional sewers and grinder pump systems," Small Flows, October 1991, p 4. Courtesy of Heather Groves, NAHB Library and Information Center. 800-368-5242 Ext 204 (CD ROM search service, fees involved, for GTHBA members and NHBA members)
27. "Septic Tank/Water Softener, potential effects of water softener use on septic tank soil absorption on-site wastewater systems; the effect of home water softener waste regeneration brines on individual aerobic wastewater treatment plants," Water Quality Research Council, Water Quality Association, 477 E. Butterfield Road, Lombard IL 60148
28. "Design Handbook, Grinder Pumps, Low Pressure Sewer Systems," Environment One Corporation, 2773 Balltown Road PO Box 773, Schenectady NY 12301 518-346-6161 (Richard C. Grace, Sales Mgr.)
29. "What you should know before buying a home served by a septic system," State of Connecticut, Department of Health Services, 150 Washington St., Hartford CT 06106, via Allspect, Westhaven CT and Butterly's Building Inspection Service, CT.
30. "Soil infiltration capacities as affected by septic tank effluent application strategies," D.L. Hagett, et al, 1982, In: Proceedings of the 3rd National Symposium on Individual and Small Community Sewage Treatment." ASAE Pub. 1-82, pp. 72-84. ASAE, PO Box 410, St Joseph MI 49085, current address: ASAE, 2950 Niles Rd., St Joseph MI 49805-9659, courtesy of Bob Stead, ASHI.
31. "Aerobic on-site systems studied in New Mexico," R. Asbury and C. Hendrickson, Journal of Environmental Health 45: 86-87,
32. "Soil clogging: mechanisms and control," R. Otis, 1985, in National Symposium on Individual and Small Community Sewage Treatment." ASAE Pub. 1-82, pp. 238-250.
33. "Residential Greywater Management in California," California State Water Resources Control Board, PO Box 100, Sacramento CA 95801
34. "EPA Design Manual: Onsite Wastewater Treatment and Disposal Systems," R. Otis, et al., No. EPA-625/1-80-012 (or later edition if avail.)
35. "On-site disposal of small wastewater flows," R. Otis, Dept. of Civil and Environmental Engineering, University of Wisconsin, Madison WI

36. Private communication and "Private Sewage Disposal System," septic
        checklist developed for ITA, Inspection Training Associates, Kevin
        O'Malley, 1016 S. Tremont Street, Oceanside CA  92054, 800/323-9235
       Private communication, K. Oberg to DJ Friedman,  12/15/93, 12/16/93, 7/22/94
       Private communication, J. Appleby to DJ Friedman, 9/16/93, Venice FL
       Private communication, D. Barnett to DJ Friedman, 9/15/93, Evansville IN
       Private communication, N. Becker to DJ Friedman, 9/15/93
       Private communication, E. Fitzgerald to DJ Friedman, 9/94, Adoption of New
    Jersey environmental protection law addressing septic system operation and
    maintenance, Subchapter 12, documented in New Jersey Register, 8/21/89, Cite 21
    NJR 2635. Requires annual inspection beginning in 4th year after construction,
    describes acceptability criteria, inspection steps, conditions of failure.
       Private communication, T. Moore to DJ Friedman, 1/15/94, "Private
        Septic System Evaluation," Goshen NY, 914-294-3398
       Private communication, S. Vermilye to DJ Friedman, 1/15/94, and
        sample checklist, 914-255-8888.
       Private communication, D. Surette to DJ Friedman, 5/6/94
       Private communication, R. Klewitz to DJ Friedman, 10/1/93
       Private communication, L. Scherr to DJ Friedman, 10/1/93,
        Cascade Home Inspection, Bend OR
       Private communication, G. Reid to DJ Friedman, 12/6/93
       Private communication, G. Carroll to DJ Friedman, 11/29/93,
        Action Inspection Service, Cincinnati, OH
       Private communication, R. Johnson to DJ Friedman, 11/5/93,
        The Home Specialist, Inc., Roswell GA
       Private communication, E. Rawlins to DJ Friedman, 10/7/93, Boca Raton FL,
    and "You and Your Septic Tank, a guide to the proper operation and maintenance
    of a septic tank system," Department of Natural Resource Protection, 500 E.
    Broward Blvd, Suite 104, Fort Lauderdale FL 33394 305-765-5181,
        Broward County, FL, January 1993
       Private communication, R. and B. Williams to DJ Friedman, 11/20/93,
        Williams Home Inspection Co, Hollis NH
       Private communication, A. Carson and R. Dunlop to DJ Friedman, 2/6/92,  11/10/93
       Private communication, L. Cerro to DJ Friedman, 8/22/93
       Private communication, R. Passaro to DJ Friedman, 9/15/93, 10/15/93,
    Res-I-Tec Corp., Bethel CT; also see Passaro's "Private Sewage Disposal, Some
    Suggestions," NY Metro ASHI Seminar, October 1993 (cc on hand)
       Private communication, J. Falcone to DJ Friedman, 10/15/93
       Private communication, C. Greenberg to DJ Friedman, 9/9/93
       Private communication, V. Faggella to DJ Friedman, 9/14/93,
        9/24/93, Yorktown Heights, NY
       Private communication, R. Stead to DJ Friedman, 9/20/93, Charlton MA
       Private communication, T. Lewis to DJ Friedman, 9/20/93,
        Lewis Home Inspection, Lawrenceville NJ
       Private communication, G. Guarino to T. Lewis, 12/12/91, Septic system
    failure and inspection limitations, Township of Hopewell, Department of Health,
    201 Washington Crossing, Pennington Rd., Titusville NJ  08560
       Private communication, C. Eldredge to J. Falcone,  3/27/91, Septic
    Certification and Testing Information from the Pennsylvania Septage Management
    Association, Curt Eldredge, General Manager, Wastewater Management, Inc., West
    Chester PA  19380  215-436-4045.
    

37. Wells and Septic Systems, 2nd Ed., Max and Charlotte Alth, Rev. by S. Blackwell Duncan, Tab Books, 1992 ISBN 0-8306-2137-7
38. Onsite Wastewater Treatment Systems, Bennette D.Burks, Mary Margaret Minnis, Hogarth House Ltd., 1994, ISBN 0-9641049-0-3
39. The Septic System Owner's Manual, Lloyd Kahn, Blair Allen, Julie Jones, Shelter Publications, 2000, ISBN 0-936070-20-X

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