Inspecting Difficult Septic System Sites: steep, lakeside, rocky InspectAPedia® -
Where to look outside for evidence of septic failure, difficult sites, steep or rocky sites
What other site clues indicate a probable septic problem?
How to perform a septic loading & dye test, step by step
Questions & answers about septic systems installed on difficult, rocky, or steep sites
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This document describes how to look for visual evidence of septic failure without or before testing a septic system and also
difficult site conditions that may require special measures to install a working septic system. Our page top photo shows a fresh pile of rock and soil pushed over the edge of a steep rocky embankment near where we understood a septic tank to be located. Even before beginning our inspection we were concerned about what we might find since this was a difficult septic site.
A separate article, FAILURE SPOTS,
part of our STEP BY STEP SEPTIC TEST procedure, describes where you're likely to see actual evidence of septic failure during a loading and dye test.
Looking for these conditions can give key information about the condition of the septic system before (and perhaps without) performing a septic loading and dye test
and also before (and perhaps without) invasive septic system inspection measures such as excavation.
Use of this information at other websites is prohibited; reproduction in electronic or printed form is prohibited.
How to Inspect DIFFICULT SEPTIC SITES - Indicators of Difficult Septic Installation Sites
Septic System Near a Stream exposed to flooding: at homes along Wappingers Creek in Dutchess County, NY, many septic tanks and drainfields are close to the waterway. Seasonal flooding such as shown in this photo make drainfield floods likely.
Even when flood conditions are not present, some drainfields may be too close to the creek to comply with state building and health codes, and worse, the high water table near the creek may prevent such systems from adequately treating septic effluent before it is discharged into the environment. Up-slope drainfields with effluent pumps or other special measures may be needed.
Dye tests of septic systems close to a lake or stream like this will sometimes discover that a property owner having a failing septic system succumbed to the temptation to simply run an effluent discharge line right from the end of a bad drainfield into the stream. Remember to look both above and below the water line for unexplained pipes in the area.
Steep Slope or Steep Site Septic Systems: If the building site is steep then special measures may have been needed to provide a working drainfield, or septic tank and field components may not be located near the building they serve and a pumping system may have been needed. Be on special alert for evidence of septic effluent breakout down-slope and at the bottom of steep slopes if septic components are nearby. See STEEP SLOPE SEPTIC DESIGNS for details of how septic system need to be installed on steep or sloping sites in order to provide a working and durable drainfield.
Rocky Site Septic Systems: if there is insufficient depth of soil, proper treatment of septic effluent may be impossible using a conventional septic tank and drainfield. At some sites including the one shown in our page top photo, there may be so little topsoil over bedrock that there is not depth for a conventional septic tank to be buried. At such sites an installer may provide a "low boy" septic tank - one that obtains its volume by spreading over a larger footprint but with a shallow septic tank.
Shallow septic tanks may need special or more frequent pumping, and should be taken as an alert to inspect the D-box and drainfield carefully. A drainfield or soil absorption system needs (typically) about 2 ft. of soil below the bottom of the drainfield and the top of any nearby rock or high ground water. So a drainfield installed in just a couple of feet of soil over bedrock is not going to perform well and may not be approved by local health officials.
Flat septic site near a lake: The land shown in this photo was a new home site which not only had standing water, but had only a few feet
of elevation between the yard top grade and the top of the nearby lake also shown in the photo.
The pipe shown was a footing drain emptying at the edge of a nearby lake. The septic tank and drainfield were buried in this area. I couldn't imagine how a conventional
septic tank and drain field would work in this location.
Here is a photo of the septic tank being installed at this property. That downspout
you see spilling by the foundation needs to be extended away from the home, but not where the roof drainage will simply enter the septic tank
and flood the leach field.
Here is a photo of the end of the home footing drain, higher than where
the bottom of a leach field trench needs to go, and spilling into the lake.
Here is a photo of the contractor's "repair" of the exposed footing drain and minimal soil depth at the property.
I can't inform readers of what the building department ultimately had to say about this installation.
Septic Site slope and runoff: Is surface runoff, sump pump drainage, storm drainage, or building roof runoff directed onto the septic tank or drain field area? (Risks flooding
the system.)
Vehicle areas near Septic Tanks or Fields: Is there evidence of driving or parking on the leachfield or over a tank? (Risks damaging the system or dangerous collapse.)
At the property shown in this photo, the truck is parked over a "low boy" septic tank which was installed over bedrock.
The rock pile shown at the top of this page was behind this truck and pushed over the embankment to cover a failed seepage pit - there was no working drainfield at this site.
Soil conditions before septic test start: What are soil and site conditions before start of the test: are there wet areas, evidence of surface
discharge of effluent or sewage, green grassy or soft, suspect areas?
Odors? It is important to be able to record
these conditions and their extent before and after testing.
Mound systems vs. original site: Has the mound system been constructed over a natural surface drainage path or stream? Are trees and stumps sticking
out of the mound (meaning it was used to bury site debris not to make a proper absorption field)?
Questions & Answers regarding this article
Questions & answers about septic systems installed on difficult, rocky, or steep sites
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Additional technical contributors & reference sources for this article are listed below.
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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 Capacity vs Usage in Daily Gallons of Wastewater Flow, calculating required septic tank size, calculating septic tank volume from size measurements
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
Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
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), Advanced Onsite Wastewater Systems Technologies.
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 we 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
Planting Over Septic System Component", Daniel Friedman (author/editor, InspectAPedia.com), The Innovator, Winter/Spring 2008, BCOSSA, British Columbia OnSite Sewage Association, 201-3542 Blansard St., Victoria BC V8X 1W3 Canada
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.
Test Pit Preparation for Onsite Sewage Evaluations, State of Oregon Department of Environmental Quality, Portland OR, 800 452-4011. PDF document. We recommend this excellent document that offers detail about soil perc tests, deep hole tests, safety, and septic design. Readers should also see Soil Percolation Tests and for testing an existing septic system, also see Dye Tests
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.
The NSFC Products List has an excellent list of design manuals/modules available from their website or by telephone 800-624-8301
Submissions welcome. send us a suggested document link or request an exchange of website links
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