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What things should you never flush down the drains and into a septic tank?
What items and chemicals are safe to flush down the toilet and into a private septic system? What may damage the septic tank or leach fields?
This document explains how to extend the life of the septic system by being careful about what goes into it. Discussed: List of chemicals, objects, and trash items that it would be should NEVER be flushed down a toilet Cat litter, dryer sheets, disposable diapers, drugs, coffee grounds, & lots of other stuff should not go into the septic tank nor down a drain into a public sewer.
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.
List of chemicals, objects, and trash items that should NEVER be flushed down a toilet
at TOILETS, DON'T FLUSH LIST we introduce the topic of stuff that should not be flushed down drains and into septic systems, and we explain the sorts of problems that can occur: drain clogging, sewage backups into buildings, costly septic system failure, and environmental contamination.
Here we list items that should never be flushed down a building drain much less onwards into a septic tank.
Antibiotics, used in quantity, particularly in hospitals or nursing homes that are served by onsite wastewater treatment plants, can kill off bacteria in the septic tank as antibiotics are excreted in urine.
In our opinion, however, occasional use of antibiotics by one household member in treatment of a non-chronic illness are not likely to have a lasting impact on the septic system.
Baby Wipes & Baby "Disposable" Diapers (here modeled by my grandson, Tanner D., but discretely hidden in the photo) and many other items which are not biodegradable will simply clog a septic system and are very likely to clog building drains.
Other items that people may think about disposing-of by flushing down a building drain, such as chemicals or unwanted cooking oil are contaminants or can clog or damage the drainfield.
Clothes dryer sheets used as fabric softener or to make your dry clothes "smell nicer" - the quantity of chemical in these sheets is unlikely to be sufficient to damage the septic tank bacteria, but the synthetic fabric from which dryer sheets are made will not break down in the septic tank.
These items not only add to the solid waste in the septic tank, a dryer sheet might clog the septic tank inlet at the baffle.
Condoms won't clog a pipe but like some other debris, because they are of modest size and are quite flexible, but condoms are (usually) not bio degradable. So we listed condoms, or other latex products such as latex gloves above as "never flush".
A condom in the septic tank will probably join other debris in the tank's floating scum layer, and will be removed at the next tank pump-out. Of course, if
Dirt - such as from people who clean their flower pots in the bath tub or in a "potting sink"
Cotton swabs (Q-tips(R)) have been known to clog a drain or two - not biodegradable, though trivial in volume. BUT if your system uses a septic pump or grinder pump or sewage ejector pump, this material can clog the pump impeller and cause expensive pump damage or motor burnout.
And the plastic sticks used by some cotton swabs and that are flushed through public sewers have been reported to remain indefinitely in the environment, ending as ultra-fine plastic fragments in the ocean, on remote beaches, even in sea life.
Chemicals: photo chemicals (see page top photo), paints, thinners, oils, varnishes, pesticides, used motor oil, unwanted cooking oil should never be flushed down a toilet nor put into any other building drains.
Cigarette butts are not biodegradable and should not be flushed into the septic system.
And the filters on cigarette butts can clog and destroy septic pumps.
Diapers, cloth, disposable, cotton, paper, plastic should never be flushed down a toilet.
Things like a baby diaper, modeled here by this really cute granddaughter, Sophie,
that is, little nappies and other things that do not dissolve in water or are generally not biodegradable, things that are big enough to risk
clogging a drain line, if flushed down a toilet, at the least, increase the pumping frequency needed at the
tank, and at the worst, may damage the system leading to costly repairs.
Dental floss - is not biodegradable, though trivial in volume. BUT if your system uses a septic pump or grinder pump or sewage ejector pump, this material can clog the pump impeller and cause expensive pump damage or motor burnout.
Dirt - such as from people who clean their flower pots in the bath tub should never be flushed down a building drain
Disposable wipes - such as baby wipes or personal hygiene wipes, even products described as "biodegradable" or "OK for use in septic systems" may NOT be OK: if your system uses a septic pump or grinder pump or sewage ejector pump, this material can clog the pump impeller and cause expensive pump damage or motor burnout.
Drugs, prescription or prescription medicines, should never be flushed down a toilet unless your pharmacist or the drug
manufacturer tells you specifically that the particular drug is absolutely harmless to the environment.
Kitty litter into the septic tank? cat litter should never be flushed down a building drain.
Cat litter is a material that includes
mostly clay particles (bentonite clay)
that clog pipes and
add solid waste volume in the septic tank
that will not break down in the septic tank.
This warning includes those "clumps" of cat litter from special clumping litter that solidifies around cat urine or cat feces.
It's tempting to just toss these clumps of animal waste into the toilet and flush away. But clumps of cat litter or cat litter bound by cat urine add to the solid waste load in the septic tank.
Our photo (left) shows conventional cat litter in a glass of water. There can be no doubt that this material settles to the bottom of a septic tank where it adds to the solid layer just as you see in this lab photograph.
Zeolite is the prime ingredient in cat litter. This clay-like material is used in other products and has even been under experimentation for use in capturing radioactive material [at REFERENCES] in ground water near Lake Erie.
What about other cat litter products that are advertised as "flushable" kitty litter? Some of these products, described as biodegradable, are made of processed newsprint, corn cobs, or wheat by-products.
OPINION: with the data at hand we do not believe that these products should be put into the septic tank unless their total monthly volume is absolutely trivial (a cubic foot or less). All cat litter products add solid waste or floating scum layer waste that adds to the septic system load.
Certainly we wouldn't flush newspapers down a toilet in any form. Nor corn cobs nor wheat. It is unlikely that these products dissolve in the septic tank in the same manner that does toilet tissue. Even if such a product does "dissolve", if it is present in volume it may interfere with septic tank bacterial action.
FACT: We don't know how these flushable products actually perform in the septic tank - do they float, settle, or dissolve? Is there independent supporting research by any of the sellers?
Meanwhile, if cat litter of any form has already been flushed into the septic tank it may be useful to open and pump the septic tank ahead of schedule, evaluate the level of solids in the tank, and in the future, open, pump, and inspect more often where these products are in use, until hard evidence shows that there is no discernable increase in the volume of solids, floating scum layer, nor interference with bacterial action in the septic tank.
(Research reports are invited.)
The cost to clean out clogged septic or sewer lines tells a the story. We recommend that you dispose of kitty litter waste in sealed garbage bags, not in your toilet.
Latex condoms, gloves, or similar products - we discuss condoms in septic systems further in the next section of this article.
Paper towels and facial tissues (Kleenex(TM)) do not break down easily and should not be flushed into the septic system. Toilet paper breaks down quickly and should not be a problem in an ordinary septic tank system.
Panty liners should never be flushed down a building drain.
Plastic bags or other plastic scrap or trash of any kind should never be flushed down a building drain
Sanitary napkins should never be flushed down a building drain.
Swimming pool chemicals and swimming pool back-wash water should never be flushed into a septic tank. It may seem surprising but we've been asked if it was ok to discharge swimming pool into a septic tank
High volumes of water from a pool into a septic tank will flood the tank and prevent proper processing of the waste therein
High volumes of water from a pool backwash onto a drainfield will flood the field and prevent proper processing of the septic tank effluent that is meant to be discharged there.
You should not discharge swimming pool backwash into a septic tank, ever
You should not discharge swimming pool backwash anywhere within 100 feet of a drainfield..
See details about the effects of swimming pool backwash water volume, flow rate, and chlorine
Trash and scrap such as dental floss should not be flushed down a building drain
Toilet seat covers - stronger paper toilet seat covers may be flushed into public sewers or commercial septic systems using suitable grinder pumps but are likely to clog the buidling drain or sewer piping or septic tank when flushed using a gravity flush toilet or sent into a septic tank.
Toys should never be flushed down a building drain - this may seem odd, but little kids may toss a toy car, doll, or other object into the john where it's at risk of causing a costly clog.
At an apartment in Wappingers Falls, NY, the guest toilet frequently clogged and overflowed. We finally removed the toilet to find a huge toy bone wedged across the drain.
Prior owners' dog perhaps had been washing off his treat. Had the bone moved end-ways into the drain this could have been a more costly repair.
Underpants - or other cloth items. My grandson Chase P., learning to use the toilet, flushed his new underpants down the drain because they were wet (12/09/2006 CPG), leading to a troublesome drain clog and toilet overflow problem. Cloth does not degrade in a septic tank.
We suggested that JAIL might be in his future [image] if he did this trick again, but as the photo indicates, he was not very worried. Actually it's quite common for small children to flush toys, diapers, underpants, or just about anything down the toilet. Something to be avoided.
Child Safety Warning about Toilets: an open toilet can be a child drowning hazard. Toilet lid locks are available for use in households
Water Softener regeneration cycle discharge water is likely to contain high levels of salts and possibly also other minerals that can significantly harm the drainfield or soakaway bed of a septic system by killing off soil bacteria and by forming a salt-crust in the absorption trench.
High volumes of wastewater from frequent regen cycles or worse from a water softener that is not working properly, perhaps stuck in "regen" mode, can also flood a drainfield and destroy it.
Water in large quantities from roof gutters or surface runoff should always be directed well away from
the septic tank and drainfield areas and should never be discharged into the septic system.
A septic system for handling
onsite wastewater is designed to handle normal household wastewater flows from showers, sinks, tubs, laundry, etc., not
roof runoff or surface drainage. Do not let roof gutters or surface runoff drain into an area where that water can enter the septic tank or drainfield.
Water from a high or rising groundwater level that reaches within a foot or so of the bottom of a drainfield trench is likely to prevent the drainfield from discharging treated effluent properly into the environment.
Such septic field designs are prohibited in some jurisdictions and are regulated by code such as the Massachusetts Title 5 Septic law.
Wet wipes & disposable wipes: should not be flushed into toilets. Apparently most of these products do not break down and can cause costly clogs of plumbing systems, sewer systems, and septic systems.
Watch out: Do not flush "disposable" wet wipes, baby wipes, clothes dryer sheets, sanitary napkins, nor any cloth or fabric waste into toilets anywhere, regardless of whether the toilet is connected to public sewer or private septic system.
Continue reading at BETTER NOT TO FLUSH or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.
Thanks to reader Megan O'Connell for discussion of biodegradable cat litter disposal in septic tanks 04/2009.
"It Blocks Cat Odors And Maybe Radiation - material used in litter is tested in sopping up nuclear contaminants", Andrew Revkin, New York times, 24 February 2000, p. B1. This article describes testing of cat litter used in a trench filled with zeolite (cat litter) to form a wall to intercept radioactive contaminated ground water seeping towards a stream that empties into Lake Erie. The article explains that zeolite is a family of 48 minerals that absorb odors and moisture, found in various brands of "animal litter". The most abundant mineral in the zeolite family is clinoptiloite that has a strong affinity for strontium 90.
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.
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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