Septic Tank Condition - How to Inspect Septic Tank Baffles InspectAPedia® -
Inspection & Repair Guide to lost, rusted, or damaged septic tank baffles
Causes of septic tank baffle damage
Effects of septic tank baffle damage on the septic drainfield life
Flooded septic tanks - how to detect leaks into the septic tank by examining the septic tank baffles
How to detect a lost or damaged septic tank baffle - when to add a septic tank tee
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This document describes how to inspect the condition of septic tank baffles at the septic tank inlet baffle and septic tank outlet baffle ports. Our page top photo shows a typical concrete septic tank baffle at the inlet pipe. Steel septic tanks have a similar barrier installed.
Septic tank baffles are a key component of septic tanks which prevent damage to the drainfield by reducing effluent agitation as sewage enters the septic tank, and
by preventing solids from flowing out of the tank to the drainfield. If the septic tank baffles are damaged, missing, or were never provided in the first place, the life of the drain field or leach field will
be seriously shortened. Inspecting concrete septic tanks is a key component in onsite wastewater disposal systems. See SEWAGE LEVELS in SEPTIC TANKS for details on normal and abnormal levels and what they mean.
If your septic tank baffles are damaged and need repair or replacement, see SEPTIC TANK TEES how to install septic tank tees when tank baffles are damaged or missing. It's an easy repair. We also recommend septic tank outlet filters installed at the tank outlet tee to extend the drainfield life. See Using Septic Filters.
This is a chapter of Septic Systems Inspection, Testing our online book about septic system inspection procedures,
defects in onsite waste disposal systems, septic tank problems, septic drainfield problems, checklists of system components and things to ask.
Readers of this page who discover that their septic tank baffles need repair should see Septic Tank Inlet and Outlet Tee Installation Details.
SEPTIC TANK BAFFLES - Inspecting the Condition of Septic Tank Baffles
If at the septic tank outlet the baffles are damaged or missing, or if no replacement "tee" has been installed, you can be sure that sewage has been pushed into the drainfield or absorption system, reducing its future life by speeding soil clogging there.
How to Find & Repair Lost or Rusted Septic Tank Baffles
If septic tank 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.
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). The steel septic tank shown above at left
has a baffle that is rusted away at its top. On pumping this old steel septic tank one expects to see the baffle bottom has rusted off too.
The home made septic tank shown above at right had no inlet baffle and a broken outlet baffle, factors in the rapid destruction of the leach field
for this septic system.
Broken septic tank 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.
Our photo (left) shows an old steel septic tank with the baffle at the right side of the photo. Just touching the baffle with a tool showed us that it was rusted and collapsing. This septic tank was pumped out, filled-in, and abandoned. But had the owners intended to use it they'd have needed to excavate the tank to install a baffle. That procedure is described in detail at SEPTIC TANK TEES.
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.
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.
As we mentioned above, see SEPTIC TANK TEES for instructions on how to install septic tank tees when septic tank baffles are damaged or missing.
Concrete Septic Tank Baffle Inspection
Inspect for Damaged Septic Tank Baffles at Inlet & Outlet:
The condition of the septic tank baffles tells you what has been happening in the septic system.
Our photo at left, compliments of architect Jerry Waters, shows a badly deteriorated concrete septic tank baffle. Details of the septic tank baffle repair, involving installing a PVC tee in this septic tank, are shown at SEPTIC TANK TEES.
Concrete septic tank baffles may erode from chemicals, detergents, poor concrete mix,
water flowing over top of baffles, or may be broken by improper pumping procedures.
Look for evidence that the floating scum layer is over or has ever been over the tank baffles - an
indication of system failure that needs further investigation.
Inspecting for Septic Tank Baffle Overflow
When a septic tank is opened for tank pumping at a center cleanout port the baffles are not easily visible except indirectly by mirror or camera held inside the tank.
However for this case we opened and inspected the septic tank inlet baffles.
This photo shows inlet sewer line (green pipe at left) and concrete baffle (at right) at the inlet end of a 1000 gallon concrete septic tank which is in use.
While the sewage level looks normal in the tank at the time of this photo, the sewage atop the concrete tank baffle suggested that the septic tank had been flooded in the past.
We were concerned by the evidence that sewage had been flowing over the top of the baffle - an abnormal condition that could suggest a prior blockage either at the tank inlet baffle or at the tank outlet.
We decided to pump the tank, clean it, and inspect it further. The step by step septic tank opening, pumping, and inspection procedure are documented at SEPTIC TANK PUMPING PROCEDURE.
Flooded Septic Tanks due to Leaks Into the Septic Tank
Ground water or surface runoff leaking into a septic tank will flood the tank and add to saturation of and early failure of the septic system leach field or drainfield. At the septic tank shown in these photographs, water was leaking into the septic tank around the tank inlet sewer pipe.
We located and corrected the probable source of water leaking into the tank. In this case the leak was at the inlet pipe to the septic tank where water was collecting by running
down the hill into the sewer line trench. The combination of a downhill trench headed towards the septic tank (the trench collects and aims surface and subsurface runoff water towards the septic tank), and a leak at the entry of the sewer pipe into the septic tank was causing the tank to flood.
We sealed the entry to the septic tank with concrete
as shown in this photo of a concrete seal which we installed at the sewer line entry to the septic tank.
See Septic Tank Leaks - for an explanation of how and why septic tank leaks cause septic system failures.
You cannot see the entire condition of the septic tank baffle before the tank is pumped, but inspect the baffle tops for evidence of corrosion, damage, total absence, or of sewage flowing over the baffle top (an indication of excessive in-tank sewage levels). Photos of the septic tank baffles in a concrete tank, as seen from
inside the septic tank are provided at "Septic Tank Pumping Procedure" for which we provide a link at "More Reading" below.
The sewage level inside a septic tank should always be several inches below the baffle top but within a right at at or just below the bottom of
the tank inlet pipe. If sewage level is low inside a septic tank which is in use, it is almost certain that the tank has been damaged and is leaking into
surrounding soil.
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 at SEPTIC TANK PUMPING SCHEDULE. Also see MEASURE SCUM & SLUDGE for details of how we make these measurements.
Readers who discover that their septic tank baffles need repair should see SEPTIC TANK TEES: "Septic Tank Inlet and Outlet Tee Installation Details".
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Additional technical contributors & reference sources for this article are listed below.
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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.
AEROBIC SEPTIC SYSTEMS
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 Manua [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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