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Diagnose the cause of soakbed or leachfield failure:
This article explains how to detect and diagnose a clogging failure of the septic drainfield or leachfield as one of the 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"?
How can you distinguish between a blocked pipe, a septic tank that
needs pumping, and a clogged drainfield that needs replacement? This is an important question as it distinguishes between relatively
low cost maintenance or repair task and a costly septic leach field replacement.
We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.
Evidence of Septic System Effluent Disposal or Drain Clogging Failures
[Click to enlarge any image]
In simplest terms, there are several visible septic effluent or onsite wastewater disposal failures accompanied by several other indicators that the soakaway bed, drainfield, or leaching beds are in trouble:
Slow drains are the symptom of septic system field failure that people often notice first, though slow drains can also be caused by drain blockages or plumbing vent defects. If you have to flush a toilet repeatedly to get waste to exit the bowl and provided that the water volume used is normal at each flush, then there's a problem not to be ignored.
Wait too long and a slow toilet flush becomes a costly sewage backup cleanup project or if not repaired promptly you may face a building flood and mold contamination cleanup project in addition.
Watch out: pumping the septic tank can give temporary, emergency relief to a slow flush or drain backup problem due to a failing septic system, but depending on the daily volume of wastewater produced, the tank will fill up again in just a few days (or less).
Pumping the septic tank doesn't fix anything. If you are pumping the septic tank at abnormally frequent intervals the septic system is in trouble and needs repair or replacement. Pumping the septic tank on regular schedule (SEPTIC TANK PUMPING SCHEDULE) can extend drainfield life but if the field has already failed all you obtain is temporary relief - and the ability to flush toilets until the septic tank fills again in 1 to 7 days.
Sorry but SEPTIC DRAINFIELD RESTORERS? are also not likely to fix the trouble and some contaminate the environment and are illegal in most jurisdictions.
Toilets or other fixtures back up into the building when the drain blockage or septic failure is more extreme - but
before assuming a slow drain or backed-up toilet is due to a failed septic system, first see CLOGGED DRAIN DIAGNOSIS & REPAIR then return here using your browser's "BACK" button. You may also need to see TOILET REPAIR GUIDE.
Effluent or sewage appears at the surface of the yard, or the neighbor's yard! (Also called septic breakout or effluent breakout).
At SEPTIC FAILURE SPOTS we describe where effluent typically shows up when the disposal field is failing.
At above left we show septic effluent flowing over rock down-hill and some distance from the actual septic tank and seepage pit.
You may find evidence of septic failure by improper effluent discharge that is not immediately obvious, such as effluent showing up in a nearby drainage ditch or even as abnormal algae growth in a nearby lake, stream, or pond (photo at left) where high levels of nitrogen in the wastewater encourage an algal bloom like this one.
When there is an argument about whose septic system has failed, yours or your neighbors, or when we're not sure if the wet area is due to surface runoff or to septic system failure, a septic dye test can sort out the question.
If you find these conditions the septic system has probably been in failure for some time in that it has not been adequately treating the effluent.
Distribution box abnormal conditions: check the distribution box that feeds individual absorption field lines for tipping, effluent back-flow from the fields, solid sewage, or inadvertent un-balanced flow into the various drainfield lines or sections.
Greener grass: is the grass greener over the septic tank? Not necessarily, both because soil backfill depth may be less in that location and because while effluent may leak out of a septic tank more often it leaks to the ground surface in the area of the disposal field itself.
Septic odors may also indicate a system failure or an imminent failure. Septic or sewer odors are not always noticed when a drainfield has failed nor when drains are clogged. And such odors
may also be produced by defects in the plumbing vent system or other site conditions.
Septic tank inspection can also give evidence of drainfield failure such as abnormally high sewage levels in the tank (over the baffles - SEPTIC TANK LEVELS of SEWAGE) or wastewater re-entering the tank from its outlet during tank pumping
High wastewater may also be due to SEPTIC TANK LEAKSinto the septic tank not just due to a failed drainfield.
Discovery of very high sludge levels or scum layer thickness (MEASURE SCUM & SLUDGE ) indicates that the tank was not pumped often enough. Failure to maintain enough open or free area in the septic tank pretty much guarantees that solids have been flowing into and shortening the remaining life of the absorption bed or drainfield.
Understand the Cause of Septic Field Failure to Determine What Repair is Needed
Typical causes of septic system disposal field failure range from things that are easy and cheap to repair, to a need for complete system replacement:
Clogged building drain or septic system effluent distribution pipes - see
Broken drain pipes or septic effluent distribution piping anywhere in the system, starting between the building and the septic tank or even inside the building.
SEPTIC TANK, HOW TO FIND and related articles can help trace piping.
Damaged septic tank - if the tank baffles are damaged it's easy to replace them, and not costly, but you may have already sent sewage solids out into the drainfield, reducing its future life.
Tipped septic effluent distribution box - find and inspect and fix the D-box and you may be back in business. Often a tipped D-box is sending all of the septic wastewater down just a portion of the drainfield, overloading it and causing an apparent failure.
Clogged drainfield or soakaway field absorption soils around the drainfield piping or trenches, (often by salts, grease & solids, or by an over-aged too-thick biomat) - people try magic bullets, additives, restorers, but despite testimonials and advertising by companies selling these restorers, we have had few reports of lasting, effective success. You may need a new septic drainfield, or you may be able to switch to an alternating drainfield or set of trenches to rest and recover the sluggish section.
Drainfield soils can become clogged or drainfield pipes can be broken and crushed by driving equipment over the drainfield - see DRIVING or PARKING OVER SEPTIC.
Water-saturated drainfield soil absorption area - you may need to replace the entire drainfield, switch to an alternating bed or set or septic fields, or it may be possible to direct surface and subsurface water from other sources away from the drainfield area.
Septic Tank Back-Flooding: a flooded septic tank - that is a tank at abnormally high levels or a septic tank that back-floods during or soon after it has been pumped out may explain both sewage backups in a building and might indicate a septic soakbed that is in failure.
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Question / Comment:
(May 14, 2011) Timbo68 said:
This series of articles has been EXTREMELY helpful. I discovered some nasty water oozing inot my yard. Research from these articles helped me to troubleshoot the problem and orchestarte and solution. Thank you SO MUCH!!
Question / Comment:
(July 22, 2011) ROBERT said:
WHAT SIZE OF PIPE WOULD YOU NEED ID YOU HAVE 200 GAL.A DAY WASTE WATER
Robert 200 gallons a day of wastewater is very small - about one person's worth of use. But you want to be asking what size drainfield is needed, not pipe size (diameter);
The required drainfield size (feet of pipe in appropriately constructed trenches, for example) DEPENDS on soil conditions - if the soil has slow percolation rate you need more.
If the wastewater is gray water - sinks, tubs, laundry - an ordinary drywell might suffice.
Question / Comment:
(Aug 9, 2011) KZach said:
I have two concrete block septic tanks (a gravity system) at my home and both have been pumped in the last three months. My main septic tank recently started backing up in the yard after lots of water usage indoors (laundry, showers, etc). We have also had a lot of rain recently. I know the septic tank backed up in the yard because the soil directly over the tank was wet and it smelled bad.
There was no backup in the house drains, however, the drains have been running slowly for the past few weeks and just before discovering the water in the yard I heard the toilet bubbling as I showered. Since the tank was recently pumped, I would assume that it is not full. I have a small pipe that I can open and view the water line into the septic tank from the house and it had evidence of scum in it and it has a constant water level filling about half of the pipe. The man that pumped the tank felt that the drain field was okay. He made no mention of the baffles.
Does this sound like a drain field problem? A problem with the baffles? An overloaded system? Thanks so much for your advice!
Not quite KZach.
A septic tank (or a pair of them in your case) is normally ALWAYS FULL of septic effluent and sewage. In normal family use it takes just a few days for the tank to re-fill after being pumped. The job of the tank is to retain solid sewage and perform partial treatment of the septic effluent - the liquid portion of wastewater. The effluent then flows out of the tank into a drainfield for further treatment by and disposal into the soil.
If your tanks are made of concrete block ti sounds like a home-made system, maybe undersized septic tanks or leaky tanks that admit groundwater into the tanks during wet weather. If the tanks are flooding from groundwater that can saturate the drainfield too and lead to total system failure.
Some floating scum and settled sludge are normal in a septic tank. When those layers get too thick the septic tank stops working and sends sewage solids into (and ruins) the drainfield. That's why we pump septic tanks on a schedule. On this page at Continue reading we provide an INDEX to RELATED ARTICLES that includes a live link to - SEPTIC TANK PUMPING SCHEDULE.
Septic tanks MUST have baffles to keep solid waste out of the drainfield. OTherwise it's ruined. Your pumper should have looked at those components and would surely have told you if they were missing (common on home made septic tanks) or damaged.
IN sum, sewage backups in the yard and odors are a failure that needs diagnosis. Just pumping the tank won't fix that problem.
Question: septic system is full again - is something wrong?
(Oct 13, 2014) Anonymous said:
I have a 500 gallon septic tank that serves one single wide mobile home. I had it pumped a month ago, then again 5 days ago and it is full again. Is it possible that the lateral line is clogged and if so what can I do to unclog it?
Anon: a conventional septic tank in proper working condition is always full of sewage - wastewater - from which it discharges clarified effluent (i.e. not solids) into a drainfield or absorption bed. See
Questions & answers or comments about the procedure for diagnosing a clogged pipe failure in the septic drainfield or soakaway bed
Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
Percolation Testing Manual, CNMI Division of Environmental Quality, Gualo Rai, Saipan provides an excellent English Language manual guide for soil percolation testing. Original source: www.deq.gov.mp/artdoc/Sec6art108ID255.pdf
Soil Test Pit Preparation, fact sheet, Oregon DEQ Department of Environmental Quality, original source www.deq.state.or.us/wq/pubs/factsheets/onsite/testpitprep.pdf The Oregon DEQ onsite water quality program can be contacted at 811 South Ave, Portland OR 97204, 800-452-4011 or see http://www.oregon.gov/DEQ/
Thanks to reader Michael Roth for technical link editing 6/29/09.
Septic Tank/Soil-Absorption Systems: How to Operate & Maintain [ copy on file as /septic/Septic_Operation_USDA.pdf ] - , Equipment Tips, U.S. Department of Agriculture, 8271 1302, 7100 Engineering, 2300 Recreation, September 1982, web search 08/28/2010, original source: http://www.fs.fed.us/t-d/pubs/pdfimage/82711302.pdf.
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.)
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Advanced Onsite Wastewater Systems Technologies, Anish R. Jantrania, Mark A. Gross. Anish Jantrania, Ph.D., P.E., M.B.A., is a Consulting Engineer, in Mechanicsville VA, 804-550-0389 (2006). Outstanding technical reference especially on alternative septic system design alternatives. Written for designers and engineers, this book is not at all easy going for homeowners but is a text I recommend for professionals--DF.
Builder's Guide to Wells and Septic Systems, Woodson, R. Dodge: $ 24.95; MCGRAW HILL B; TP;
Quoting from Amazon's description: For the homebuilder, one mistake in estimating or installing wells and septic systems can cost thousands of dollars. This comprehensive guide filled with case studies can prevent that. Master plumber R. Dodge Woodson packs this reader-friendly guide with guidance and information, including details on new techniques and materials that can economize and expedite jobs and advice on how to avoid mistakes in both estimating and construction. Chapters cover virtually every aspect of wells and septic systems, including on-site evaluations; site limitations; bidding; soil studies, septic designs, and code-related issues; drilled and dug wells, gravel and pipe, chamber-type, and gravity septic systems; pump stations; common problems with well installation; and remedies for poor septic situations. Woodson also discusses ways to increase profits by avoiding cost overruns.
Country Plumbing: Living with a Septic System, Hartigan, Gerry: $ 9.95; ALAN C HOOD & TP;
Quoting an Amazon reviewer's comment, with which we agree--DF:This book is informative as far as it goes and might be most useful for someone with an older system. But it was written in the early 1980s. A lot has changed since then. In particular, the book doesn't cover any of the newer systems that are used more and more nowadays in some parts of the country -- sand mounds, aeration systems, lagoons, etc.
Design Manuals for Septic Systems
US EPA Onsite Wastewater Treatment Systems Manual [online copy, free] Top Reference: US EPA's Design Manual for Onsite Wastewater Treatment and Disposal, 1980, available from the US EPA, the US GPO Superintendent of Documents (Pueblo CO), and from the National Small Flows Clearinghouse. Original source http://www.epa.gov/ORD/NRMRL/Pubs/625R00008/625R00008.htm Onsite wastewater treatment and disposal systems,
Richard J Otis, published by the US EPA. Although it's more than 20 years old, this book remains a useful reference for septic system designers.
U.S. Environmental Protection Agency, Office of Water Program Operations; Office of Research and Development, Municipal Environmental Research Laboratory; (1980)
"International Private Sewage Disposal Code," 1995, BOCA-708-799-2300, ICBO-310-699-0541, SBCCI 205-591-1853, available from those code associations.
"Manual of Policy, Procedures, and Guidelines for Onsite Sewage Systems," Ontario Reg. 374/81, Part VII of the Environmental
Protection Act (Canada), ISBN 0-7743-7303-2, Ministry of the Environment,135 St. Clair Ave. West, Toronto Ontario M4V 1P5 Canada $24. CDN.
Manual of Septic Tank Practice, US Public Health Service's 1959.
Onsite Wastewater Disposal Books
Onsite Wastewater Disposal, R. J. Perkins;
Quoting from Amazon: This practical book, co-published with the National Environmental Health Association,
describes the step-by-step procedures needed to avoid common pitfalls in septic system technology.
Valuable in matching the septic system to the site-specific conditions, this useful book will help you install a reliable system in
both suitable and difficult environments. Septic tank installers, planners, state and local regulators, civil and sanitary engineers,
consulting engineers, architects, homeowners, academics, and land developers will find this publication valuable.
Onsite Wastewater Treatment Systems, Bennette D. Burks, Mary Margaret Minnis, Hogarth House 1994 - one of the best septic system books around, suffering a bit from small fonts and a weak index. While it contains some material more technical than needed by homeowners, Burks/Minnis book on onsite wastewater treatment systems a very useful reference for both property owners and septic system designers.
Septic Tank/Soil-Absorption Systems: How to Operate & Maintain [ copy on file as /septic/Septic_Operation_USDA.pdf ] - , Equipment Tips, U.S. Department of Agriculture, 8271 1302, 7100 Engineering, 2300 Recreation, September 1982, web search 08/28/2010, original source: http://www.fs.fed.us/t-d/pubs/pdfimage/82711302.pdf
Septic System Owner's Manual, Lloyd Kahn, Blair Allen, Julie Jones, Shelter Publications, 2000 $14.95 U.S. - easy to understand, well illustrated, one of the best practical references around on septic design basics including some advanced systems; a little short on safety and maintenance. Both new and used (low priced copies are available, and we think the authors are working on an updated edition--DF.
Quoting from one of several Amazon reviews: The basics of septic systems, from underground systems and failures to what the owner can do to promote and maintain a healthy system, is revealed in an excellent guide essential for any who reside on a septic system. Rural residents receive a primer on not only the basics; but how to conduct period inspections and what to do when things go wrong. History also figures into the fine coverage.
Grass is Always Greener Over the Septic Tank, Bombeck, Erma: $ 5.99; FAWCETT; MM;
This septic system classic whose title helps avoid intimidating readers new to septic systems, is available new or used at very low prices.
It's more entertainment than a serious "how to" book on septic systems design, maintenance, or repair. Not recommended -- DF.
US EPA Onsite Wastewater Treatment Systems Manual Top Reference: US EPA's Design Manual for Onsite Wastewater Treatment and Disposal, 1980, available from the US EPA, the US GPO Superintendent of Documents (Pueblo CO), and from the National Small Flows Clearinghouse. Original source http://www.epa.gov/ORD/NRMRL/Pubs/625R00008/625R00008.htm
Water Wells and Septic Systems Handbook, R. Dodge Woodson. This book is in the upper price range, but is worth the cost for serious septic installers and designers.
Quoting Amazon: Each year, thousands upon thousands of Americans install water wells and septic systems on their properties. But with a maze of codes governing their use along with a host of design requirements that ensure their functionality where can someone turn for comprehensive, one-stop guidance? Enter the Water Wells and Septic Systems Handbook from McGraw-Hill. Written in language any property owner can understand yet detailed enough for professionals and technical students this easy-to-use volume delivers the latest techniques and code requirements for designing, building, rehabilitating, and maintaining private water wells and septic systems. Bolstered by a wealth of informative charts, tables, and illustrations, this book delivers: * Current construction, maintenance, and repair methods
* New International Private Sewage Disposal Code
* Up-to-date standards from the American Water Works Association
Wells and Septic Systems, Alth, Max and Charlet, Rev. by S. Blackwell Duncan, $ 18.95; Tab Books 1992. We have found this text very useful for conventional well and septic systems design and maintenance --DF.
Quoting an Amazon description:Here's all the information you need to build a well or septic system yourself - and save a lot of time, money, and frustration. S. Blackwell Duncan has thoroughly revised and updated this second edition of Wells and Septic Systems to conform to current codes and requirements. He also has expanded this national bestseller to include new material on well and septic installation, water storage and distribution, water treatment, ecological considerations, and septic systems for problem building sites.
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