Septic & Cesspool Safety Guide for Homeowners
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Septic System, Septic Tank, & Cesspool Safety Warnings for homeowners
Septic Tank / Cesspool Collapse Warnings
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This document outlines key septic system safety warnings for homeowners and home buyers of properties using onsite septic systems and cesspools. Septic tanks, cesspools, and drywells present serious hazards including septic cave-in's or collapses, methane
gas explosion hazards, and asphyxiation hazards. Simple precautions which we describe here can help avoid a dangerous or expensive septic problem. This document is a chapter of Inspecting, Testing, & Maintaining Residential Septic Systems.
Citation of this article by reference to this website and brief quotation for the sole purpose of review are permitted. Use of this information at other websites, in books or pamphlets for sale is reserved to the author. Technical review by industry experts has been performed and is ongoing - reviewers are listed at "References."
SPECIAL SEPTIC SYSTEM SAFETY WARNINGS FOR HOME OWNERS - Septic System Warnings for Home Owners and Home Buyers
Septic system concerns for a building owner start with safety.
The photograph at the top of this page shows what can happen when a truck drives over a cesspool, drywell, or seepage pit. Luckily in this
case no one was injured, but the seepage pit was destroyed and significant costs were involved in installing a new seepage pit
as well as in repairing the soils compacted and damaged by the heavy equipment necessary to pull this dump truck out
of the pit into which it fell.
Here are some red flags that suggest collapse hazards at septic systems, cesspools, drywells, or seepage pits:
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 or inexperienced homeowners may not notice a danger or malfunction. Homeowners should review the Septic System Safety Warnings listed above
If your home uses a cesspool, drywell, or seepage pit, be sure to review our Cesspool Safety Warnings - Specific Warnings about Cesspool Collapse Hazards.\
Cesspools or drywells that are constructed of dry-laid stone or concrete block, are especially at risk of sudden collapse if a septic service company has pumped down the sewage level in the cesspool and that risk is still greater if someone has attempted to "restore" cesspool operation or function by aerating or jetting or agitating the sludge layer on the bottom of the unit.
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.
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Additional technical contributors & reference sources for this article are listed below.
Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.
Septic Safety: (this document) Septic System, Septic Tank, & Cesspool Safety Warnings for Septic Inspectors, Septic Pumpers, and Homeowners
Cesspool Safety - Specific Warnings about Cesspool Collapse Hazards
SEWER GAS ODORS: diagnosing, finding, and curing septic tank and sewer line odors
Don't Flush these things into a septic system: a list of what's ok and what's not ok to put into septic tanks and building drains
Tank Location - How to Find the Septic Tank, how deep will the cover be, how to document its location - these methods also apply to locating a cesspool or drywell at a property.
Dye Tests: how to perform a Septic Loading and Dye Test - septic dye testing procedures in complete detail, a septic function test - a chapter in the above book.
Alan Carson Carson Dunlop Associates, Toronto, Ontario. Mr. Carson is a home inspection professional, educator, researcher, writer, and a principal of Carson Dunlop Associates, a Toronto home inspection and education firm. Mr. Carson is a past president of ASHI, the American Society of Home Inspectors
Mark Cramer Inspection Services Mark Cramer, Tampa Florida, Mr. Cramer is a past president of ASHI, the American Society of Home Inspectors and is a Florida home inspector and home inspection educator. (727) 595-4211 mark@BestTampaInspector.com 11/06
Hankey and Brown home inspectors, Eden Prairie, MN, technical review by Roger Hankey, prior chairman, Standards Committee, American Society of Home Inspectors - ASHI. 952 829-0044 - hankeyandbrown.com 11/06
Arlene Puentes, a licensed home inspector, educator, and building failures researcher in Kingston, NY. 11/29/06
John Francis, Bioworks, Inc., marketing and technical services - editing/proof reading 4/07. "BioWorks provides environmentally responsible, safe and cost-effective solutions to the agriculture industry"
Thanks to Denise Cermola for permission to use the photo above, showing a dump truck collapsed into a seepage pit. (email 11/16/06 to 12/10/06). The contractor drove over this seepage pit connected to septic tank and caused total destruction of the system.
Thanks to George Fielder who points out that methane gas is not toxic, but rather (we add) the hazards of methane gas produced by septic systems include possible explosions or the asphyxiation of someone who enters or even just leans over a septic tank opening. (email 10/20/2007)
Thanks to Donica Ben who points out the danger of digging into buried electrical wires (11/11/07)
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building design, inspection, and repair, and about indoor environment testing, diagnosis, and cleanup are at the InspectAPedia Bookstore.
Septic Tank Capacity vs Usage in Daily Gallons of Wastewater Flow, calculating required septic tank size, calculating septic tank volume from size measurements
Pennsylvania State Fact Sheets relating to domestic wastewater treatment systems include
Pennsylvania State Wastewater Treatment Fact Sheet SW-161, Septic System Failure: Diagnosis and Treatment
Pennsylvania State Wastewater Treatment Fact Sheet SW-162, The Soil Media and the Percolation Test
Pennsylvania State Wastewater Treatment Fact Sheet SW-l64, Mound Systems for Wastewater Treatment
Pennsylvania State Wastewater Treatment Fact Sheet SW-165, Septic Tank-Soil Absorption Systems
Document Sources used for this web page include but are not limited to: Agricultural Fact Sheet #SW-161 "Septic Tank Pumping," by Paul D. Robillard and
Kelli S. Martin. Penn State College of Agriculture - Cooperative Extension, edited and annotated by
Dan Friedman (Thanks: to Bob Mackey for proofreading the original source material.)
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