InspectAPedia ^®

Septic Holding Tanks in Septic System Designs InspectAPedia®  -     Holding Tanks in septic system design applications

This document discusses holding tanks in septic system design applications. US EPA information with supplemental documentation, references, and comments.

© Copyright 2009 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links 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 Holding Tanks and Septic Hauling Systems

Onsite Wastewater Treatment Systems Special Issues Fact Sheet 4 EPA 625/R-00/008

Description of Septic Holding Tank Systems

A holding tank or vault receives wastewater from a home or commercial establishment and stores it until it is pumped out and hauled to a receiving/processing facility. Although similar to septic tanks, vaults have no outlet piping and must be watertight. The volume can range from 1,000 gallons to 4,000 gallons or more. The vault should be equipped with an audible and visible high-water alarm, which alters the resident to the need for pumping.

Different sizes of vaults and tank trucks can be used; water conservation can reduce costs considerably by reducing the frequency of pumping. A vault can be equipped with a standpipe and a quick disconnect to which the pumping truck can be directly connected for efficient (minimal spillage) emptying of the vault.

Holding tanks can be used for the entire wastewater flow in cases where conventional and typical alternative systems are not feasible. They are often used this way for seasonal homes in sensitive environmental settings. Holding tanks can also be used to collect only a part of the wastewater flow. Usually, they are used to collect the greywater when non-water-carriage toilets are employed in sensitive areas.

This option permits a significant reduction (usually one-third or more) in the number of tank pumpings as compared to the whole wastewater collection option. Another holding tank option is to collect only the blackwater fraction of the wastewater while the graywater is treated in an OWTS. This option is most popular in estuarine areas where significant nitrogen removal is required because the blackwater may contain from 70 to 90 percent of the total nitrogen load. In this case the reduction in pumping frequency from the whole wastewater option would be about two-thirds.

Over and above these combinations a program to reduce water use can be overlaid. The critical contribution of such a program (see chapter 3) is to reduce the daily volume of wastewater (blackwater, graywater, or combined) produced and the required frequency of holding tank pumping. Some onsite wastewater recycling can be added to this program in arid regions where gravity feed and belowground watering of nonconsumable vegetation can be accomplished. However, such a program must meet all local public health requirements.

Applications of Septic Holding Tank Systems

Pump and haul collection is best used when soil absorption fields do not work (for example, where bedrock or ground water levels are near the ground surface) and there is no sewer system.

Typical applications are second homes, where annual occupancy may be only a few days to a few months; where a nuisance or public health hazard must be abated; where an isolated building has no running water; in temporary structures or gathering places; or where nutrients must be excluded from ground water to protect environmentally sensitive areas. Pump and haul collection may also simply be the least expensive alternative in some places.

Pump and haul systems are viable only under a wastewater authority that guarantees service. Pump and haul collection can became prohibitively expensive when homes are occupied all the time or where the distance from the treatment plant to the home is more than a few miles.

Management needs of Septic Holding Tank Systems

Holding tanks should be used only where a proper management program is in place. Construction requirement are essentially the same as for a septic tank in that the onsite testing for tank leakage is vital to a successful design and the alarm system must be dredged for proper functioning before acceptance.

In addition to timely pumping, operation and maintenance requirements should include checking the alarm function, cleaning the activation floats, and comparing volume used vs. volume accumulated in the tank. The skill requirements at the site are minimal and can be estimated as approximately 1 hour per pumping. There are normally no energy requirements; the residuals are the tank contents, and confined-space entry safety requirements must be followed if tank entry is required.

Risk management issues of Septic Holding Tank Systems

Holding tanks are not subject to upset by flow variation, toxic loads or power outages. They should be insulated and possibly heat-treated in extremely cold climates. If properly vented through the building sewer, they should not exhibit odor problems, but use in hot climates may require an increase in pumping frequency or a regular addition of lime for mitigation. There is a release of objectionable odors during tank pumping, which can cause some discomfort to residents.

Costs of Septic Holding Tank Systems

More recent cost estimates for holding tank-hauling wastewater disposal indicate that tank installation is about $1 per gallon of capacity (up to 5,000 gallons) while the alarm system is about $400.

Tank pumping is generally in range of 10 to 30 cents per gallon, to which labor, travel and equipment amortization may be added (or these costs may be included in a flat fee). Travel costs will dominate if the round-trip distance to the holding tank, to the disposal site, and back to home base exceeds 50 miles. The permit costs to discharge at an appointed sit (treatment plant, land spreading site, or independent treatment facility) is also escalated, multiple pumping from a year-round house can become extremely expensive.

Share this Article      

...

Technical Reviewers & References

Search InspectAPedia

• Daniel Friedman - principal author/editor of the InspectAPedia^® Website
• InspectAPedia Bookstore lists recommended books, organized by topic & available for purchase. Most of our articles also include a list of recommended books for the specific article topic as well as other references, and information sources.
• Critique, contributions wanted: Contact Us to suggest corrections or additions to articles at this website, and if you wish, to receive online listing and credit as a contributor. Particular thanks are due to the many experts and also consumers who read and critique technical articles at InspectAPedia.com.
• 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 SYSTEMS HOME
SEPTIC INFO ARTICLES
HOME BUYERS GUIDE to SEPTIC SYSTEMS
SEPTIC SYSTEMS ONLINE BOOK
SEPTIC PUMPING REPAIR
SEPTIC TREATMENTS
SEPTIC CONSULTANTS
SEPTIC AUTHORITIES
SEPTIC SYSTEM BOOKS REFS CODES
SEPTIC SYSTEM DESIGN MANUAL - Online
SEPTIC SYSTEM DESIGN BASICS
SEPTIC SYSTEM 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
  GREYWATER SYSTEMS
  HOLDING TANK SEPTIC SYSTEMS
  LAGOON SYSTEMS
  GRAVITY/SIPHON DOSING SYSTEMS
    Methods of Effluent Distribution
    Bell Siphon Septic Dosing
    Dipping or Tipping Dosing
    Float Control Dosing Systems
    Products and Suppliers
  PRESSURE DOSING SYSTEMS
  HOW EFFLUENT IS DISTRIBUTED
  PRESSURE DOSING SPECIFICATIONS
  MANIFOLD DOSING SYSTEMS
  RIGID PIPE DOSING SYSTEMS
  DRIP DOSING 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
  SEWAGE TREATMENT SYSTEMS
  TOILET ALTERNATIVES
  VEGETATED SUBMERGED SEPTIC BEDS
  WETLAND SEPTIC SYSTEMS
  ALTERNATIVE SEPTIC DESIGNERS
  ALTERNATIVE SEPTIC PRODUCTS

• US EPA Onsite Wastewater Treatment Systems Manual - original citation http://www.epa.gov/nrmrl/pubs/625r00008/html/fs4.htm
• Septic Tank Soil Absorption Systems - Decentralized Sysetms Technology Fact Sheet, US EPA, EPA 932-F-99-075, September 1999 - original citation www.epa.gov
• 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
• Victor Faggella, is a senior home inspector in New York and can be reached at Centurion Home Inspections, Inc. Mahopac, NY 10541. 845-628-0941 vjf@centurion-inspections.com The company has offices in Mahopac, NY, Woodbury CT., and Mansfield Center, CT.
• 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
• Rissy Plastics - Matt Cauthorn, Flout@engineer.com for text describing the Flout(TM) floating outlet valve dosing system control (see above).
• Daniel Friedman - principal author/editor of the InspectAPedia ^TM Website
• Construction Guidelines for Gravity and Flood-Dose Trench Onsite (Septic) Systems, Indiana state health department
• Maintenance of Low Pressure Distribution Septic Systems, Vermont Cooperative Extension
• Dosing Gravity Drainfield Systems, Recommended Standards and Guidance for Performance, Application, Design, and Operation & Maintenance, Washington State Department of Health, July 1, 2007

Anderson, C.D. 1986 Trucked Collection Systems Experience in the Northwest Territories. In Proceedings of Appropriate Wastewater Management Technologies for Rural Areas Under Adverse Conditions. Technical University of Nova Scotia, Halifax, NS.

Burrows, R., and N. Bouwes. The Cost of Holding Tanks for Domestic Wastewater. Small Scale Waste Management Report. University of Wisconsin, Madison, WI.

Dix, S.P. Case Study Number 4: Crystal Lakes, Colorado. National Small Wastewater Flows Clearinghouse, West Virginia University, Morgantown, WV.

Mahoney, W.D., ed.-in-chief. 1989. Means Site Work Cost Data. R.S. Means Co., Kingston, MA.

Mahoney, W.D., ed.-in-chief. 1990. Means Site Work Cost Data. R.S. Means Co., Kingston, MA.

Manci, K. No date. Wastewater Treatment Alternatives.Holding Tanks. The Pennsylvania State University, College of Agriculture, Cooperative Extension Service, University Park, PA.

Mooers, J.D., and D.H. Waller. 1996. Onsite Wastewater Research Program: Phase III. TUNS/Centre for Water Research Study, Halifax, NS.

National Association of Waste Transporters (NAWT). 1998. Introduction to Proper Onsite Sewage Treatment. National Association of Waste Transporters, Scandia, MN.

U.S. Environmental Protection Agency (USEPA). 1984. Final Generic Environmental Impact Statement: Wastewater Management in Rural Lake Areas. U.S. Environmental Protection Agency, Region 5, Chicago, IL.

Waller D.H., and A.R. Townshend. 1987. Appropriate Wastewater Management Technologies for Rural Areas Under Adverse Conditions. Special Publication, Technical University of Nova Scotia, Halifax, NS.

More Information on Building Diagnostic Inspections and Repairs

• The Septic System Information Website home page for this topic
• Septic Systems Inspection, Testing, & Maintenance- online textbook. Detailed how to inspect, maintain, repair information
• The Home Buyer's Guide to Septic Systems
• Septic Tank Pumping Guide: When, Why, How to pump the septic tank
• Home & Outdoor Living Water Requirements
• Septic Tank Capacity vs Usage in Daily Gallons of Wastewater Flow, calculating required septic tank size, calculating septic tank volume from size measurements
• How Big Should the Leach Field Be? - table of soil percolation rate vs. field size
• Septic System Drainfield Absorption System Biomat Formation - what leads to drain field clogging and expensive drainfield repairs
• Table of Required Septic & Well Clearances: Distances Between Septic System & Wells, Streams, Trees, etc.

InspectAPedia® Home & Site Map - Building & Environmental Inspection, Testing, Diagnosis, Repair, & Problem Prevention Advice: In-depth research & advice on diagnosing, testing, correcting, & preventing building defects & indoor environmental hazards. Unbiased information, no conflicts of interest.

The Mold Information Center: What to Do About Mold in Buildings, When and How to Inspect for Mold, Clean Up Mold, or Avoid Mold Problems

Use this simple, economical mold test kit by following our instructions on how to collect and mail mold samples to our lab

Environmental Inspection, Testing, & Diagnosis On-Site IAQ, Gas, Air Testing, Mold Investigation, Sick Building Diagnosis, Lab Services, & Remediation Plan Preparation - indoor air quality testing, problem source determination, supporting lab work, written remediation plan addressing removal of environmental and other hazards and prevention of their recurrence.

Building Inspection, Problem Diagnosis, Forensic Investigation & Testing, Repair Consulting

Contact Daniel Friedman for website content suggestions or for fee-paid consulting