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Toilet don't flush guide:
What items and chemicals are safe and what items are not 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.
We provide a list of articles giving exact details about items that should not be flushed down building drains either because of the probability of clogging the drain waste vent system or because of the risk of chemical harm to necessary septic tank and drainfield bacteria, or finally, because of the risk of chemical contamination of groundwaters, nearby leaks, ponds, streams, and the environment in general. We also discuss & provide citations about chemical contaminants found in residential wastewater.
What Solids, Liquids, Chemicals, Treatments & Other Stuff Should Not be Flushed Down Toilets or Other Building Drains?
What Solids, Liquids, Chemicals, Treatments & Other Stuff Should Not be Flushed Down Toilets or Other Building Drains? - Complete guide to what is OK or NOT-OK to flush down the toilet and into your septic tank. Article List for what is ok or not ok to flush down your drains. Chemical Contaminants Found in Residential Wastewater & Their Sources. "NO FLUSH SUMMARY LIST provides a free printer-friendly list of things to avoid flushing down the toilet.
Diapers, sanitary napkins, tampons, photo chemicals, cleaners, garbage and even toys which find their way into building
toilets and drains risk clogging the drain piping,
distribution piping, or the septic tank baffles. In the photo at left, the inspector pointed to the bottle of acid and
wondered how much photo chemical had gone into the septic system and worried about what that might mean for the health of the leach field.
Even if the septic drainfield field
appeared to be "working" it might not be properly treating the septic effluent. It's best to keep diapers, sanitary napkins, chemicals,
and the like out of your building drains and toilets. Garbage disposers also increase the solid waste load on septic
tanks and may require that the tank be pumped more often.
Diapers, toys, garbage which find their way into building toilets and drains clog drain piping,
distribution piping, or septic tank baffles and fields. Keep diapers, tampons, sanitary napkins, household chemicals,
and the like out of building drains and toilets.
Garbage disposers also increase the solid waste load on septic
tanks and may require that the tank be pumped more often.
SEPTIC TREATMENTS & CHEMICALS - are not required, not recommended, and in some jurisdictions are prohibited for conventional septic tank & soakaway bed systems and in some cases can cause damage to the system or can cause spread of contaminants in the environment. Exceptions to the generally-true "use no septic treatments" can arise however for some advanced-design septic systems such as some aerobic or biologically-accelerated treatment (BAT) septic system designs.
See SEPTIC TANK BACTERIA BOOST
SEPTIC TREATMENT FAQs - questions & answers about the need for and usefulness of septic tank treatments, chemicals, enzymes, or drainfield/soakbed restorers
Chemical Contaminants Found in Residential Wastewater & Their Sources
The focus of our "do not flush" advice provided in the article list above is practical: we list substances which are known to result in septic system blockage, clogging, failure, or contamination.
That more broad approach includes non-toxic materials such as coffee grounds and baby diapers or tampons, as our focus is on septic system maintenance and on preserving the proper functioning of the system piping as well as the health of the bacteria needed in the septic tank and in the absorption bed or soakaway bed to process various pathogens.
A very wide range of chemical contaminants can be found in residential wastewater, as a 1980 US EPA study documented in citing 129 contaminants that were targeted for survey. However the chief tables most often cited in that study don't address concentration levels nor drainfield effects, and the study pointed out the difficulties in surveying private homes and uses of products that can produce chemical contaminants in wastewater.
[Our photo (above left) illustrates a source of chemical contaminants: dumping photo-chemicals down the drain and into the septic system.]
Just below we provide some useful citations for further reading.
 W.D. Robertson, "Chemical fate and transport in a domestic septic system: Site description and attenuation of dichlorobenzene", Environmental Toxicology and Chemistry, Volume 13, Issue 2, pages 183–191, February 1994 -
Abstract: The mobility and attenuation of dichlorobenzene (DCB) in a septic system groundwater contaminant plume with a very detailed monitoring network was evaluated by conducting a tracer experiment in which 450 ml of a plumbing line cleaner containing DCB and 1 kg NaBr were injected into the septic system.
DCB concentrations of up to 3,460 μg/L were observed in the septic tank effluent, up to 650 μg/L in the unsaturated zone 0.45 m below the tile bed, and up to 13 μg/L at the water table at 2 m depth. Peak DCB concentrations arrived at the water table after 57 d at a source-normalized concentration of 0.02, whereas peak Br− concentrations arrived at the water table after only 10 d at a normalized concentration of 0.61, thus demonstrating DCB attenuation and retardation during migration through the aerobic unsaturated zone at this site.
Model simulations of DCB breakthrough at the water table provided an adequate fit with the field data when a retardation factor of 6.5 and decay half-life of 15 d were used. Evidence for biodegradation of DCB was provided by the occurrence of a 7-d lag (biota acclimation period), after which increased attenuation of DCB was observed in the unsaturated zone and by the preferential attenuation of two of the three isomers of DCB.
Vigorous biodegradation of trace volatile organic compounds such as halogenated and substituted benzenes was indicated in the unsaturated zone below this septic system.
 William R. Walker, Carol J. Haley, Phyllis Bridgeman and Stephen H. Goldstein, "Effects of deodorants on treatment of boat holding-tank waste", Environmental Management, Volume 15, Number 3 (1991), 441-449, DOI: 10.1007/BF02393890
Abstract: A literature search and survey of Virginia, USA, campgrounds with RV pump-out stations were used to determine whether boat holding-tank deodorant chemicals would have deleterious effects on marina septic systems or package treatment plants. Laboratory studies reported in the literature indicate that these chemical additives could affect septic system function in three ways:
(1) active ingredients in the additives can impair sewage degradation in septic tanks, causing sludge buildup and overflow of solids into the drainfield,
(2) additive chemicals might enter the drainfield and, in high enough concentrations, reduce the drainfield's ability to degrade waste, or
(3) toxic additive chemicals might migrate from the drainfield to ground or surface water.
Laboratory studies also show that some ingredients added to holding tanks interfere with functioning of activated sludge treatment process. Experience in the field and in other laboratory studies suggests that factors such as dilution of treated waste with untreated waste and the characteristics of the sewage to be treated can reduce the possibility of damage to septic and activated sludge systems.
The campground owners surveyed indicated that they have few problems with their septic systems in spite of the presence of chemical additives in the RV waste. However, most of them practice good septic system maintenance and have devised other means of ensuring that their systems function efficiently. In addition, the survey indicates that most Virginia campgrounds get only seasonal use (as would marinas in Virginia), allowing their systems to recover between peak seasons.
 U.S. EPA, "Sources of Toxic Compounds in Household Wastewater", EPA 600.2.80, August 1980 (Author: Steven W. Hathaway, Municipal Environmental Research Laboratory, Municipal Environmental Research Laboratory. Wastewater Research Division) beginning on page 13 of that document (free from the EPA) lists 129 "target" toxic contaminants found in household wastewater along with their common sources.
Septic tank bacteria additives: exceptions to the generally-true "use no septic treatments" rule can arise however for some advanced-design septic systems such as some aerobic or biologically-accelerated treatment (BAT) septic system designs.
See SEPTIC TANK BACTERIA BOOST
Questions & answers or comments about what things harm the septic system if flushed down toilets or other building drains
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.
Watts Industries of North Andover, Mass., provides its ZRO-4 under counter system intended to target the independent water dealer market.
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
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.
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The Illustrated Home illustrates construction details and building components, a reference for owners & inspectors. Special Offer: For a 5% discount on any number of copies of the Illustrated Home purchased as a single order Enter INSPECTAILL in the order payment page "Promo/Redemption" space.
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The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume.
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