Septic Tank Maintenance: What Can or Cannot Be Flushed into a Septic Tank
Septic Tank Maintenance and Cleaning Advice

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
TOILETS, DON'T FLUSH LIST - home
- NEVER FLUSH INTO SEPTICS - separate article
- BETTER NOT TO FLUSH - separate article
- HOUSEHOLD CHEMICALS & OTHER CHEMICALS - separate articles
- CHLORINE IN DRINKING WATER & CHLORINE IN SEPTIC WASTEWATER - separate articles
- DISHWASHERS vs SEPTICS - separate article
- DRUGS INTO the SEPTIC TANK? - separate article
- GARBAGE GRINDERS vs SEPTICS - separate article
- REVERSE OSMOSIS CONCENTRATE DISPOSAL - separate article
- SEWAGE PUMP CLOG DAMAGE - separate article
- TOILET TISSUE CHOICES - separate article
- WASHING MACHINES & SEPTIC SYSTEMS - separate article
- WATER SOFTENER IMAPCT on SEPTIC - separate article
- * NO FLUSH SUMMARY LIST - separate article
Questions & Answers about what things harm the septic system if flushed down toilets or other building drains
References

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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 address and provide citations for the chemical contaminants found in residential wastewater.

What Solids, Liquids, Chemicals, Treatments & Other Stuff Should Not be Flushed Down Toilets or Other Building Drains?

Citation of this article by reference to this website and brief quotation for the sole purpose of review are permitted. Use of this information at other websites, in books or pamphlets for sale is reserved to the author. Technical review, content suggestions, critique are welcomed and are listed at "References."NO FLUSH SUMMARY LIST provides a free printer-friendly list of things to avoid flushing down the toilet.

This article is a section of our online book SEPTIC INSPECTION & TEST GUIDE whose chapters are shown at the left of this page. Citation of this article by reference to this website and brief quotation for the sole purpose of review are permitted. Use of this information at other websites, in books or pamphlets for sale is reserved to the author. Technical review by industry experts has been performed and comments from readers are welcomed. Contributors are listed at the end of each article.

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.

The tablet type toilet tank water deodorizer/flush-cleaner product such as the deodorizing hang-in-toilet-tank product shown in our photo above are discussed below at Are toilet tank cleaners that clean with every flush bad for the septic system?

Article List for what is ok or not ok to flush down your drains is given by the following detailed articles:

TOILETS, DON'T FLUSH LIST
NEVER FLUSH INTO SEPTICS - a list of the absolute "no-no's of things not to put down a drain or into a toilet.
BETTER NOT TO FLUSH - things that you'd be better off not flushing down the drains
HOUSEHOLD CHEMICALS - what household chemicals & cleaners are "ok" or "not OK" to put down drains
OTHER CHEMICALS - other chemicals to keep out of septic systems
CHLORINE IN DRINKING WATER - is this a problem for the septic system?
CHLORINE IN SEPTIC WASTEWATER - where else does chlorine come from in a septic tank?
DISHWASHERS vs SEPTICS - what is the effect on a septic system when we use a dishwasher
DRUGS INTO the SEPTIC TANK? - what is the effect on the septic tank and drainfield if we dump unwanted drugs into the system?
GARBAGE GRINDERS vs SEPTICS - is it OK to use a garbage disposal system at a house with a septic tank?
REVERSE OSMOSIS CONCENTRATE WASTE DISPOSAL - what are the effects on the septic system of RO waste water concentrate
SEWAGE PUMP CLOG DAMAGE - what things will clog or burn up a sewage pump - keep these out of your drains
TOILET TISSUE CHOICES - is toilet paper a problem in septic tanks? Should we be using special bio-degradable toilet paper?
WASHING MACHINES & SEPTIC SYSTEMS - what is the effect on the septic tank and drainfield if we use a washing machine?
WATER SOFTENERS & CONDITIONERS - do water softeners harm the septic tank or drainfield? Is water softener salt a problem for the septic system?
** NO FLUSH SUMMARY LIST ** - printer friendly list of things that should not be flushed down the toilet

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.[3] 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.

[1] 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.
[2] 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.
[3] 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.

Frequently Asked Questions (FAQs) about things that should not be flushed down drains nor into septic systems

Question: flushing toys into drains or septic systems?

can you flush toys? - Deepesh

Reply: of course not

No deepesh, I can't imagine any toy that can safely be flushed down a toilet. For example, plastics won't biodegrade in the septic tank and any toys flushed down a drain risk clogging piping. At TOILETS, DON'T FLUSH LIST you will find a more complete list of stuff to keep out of toilets, drains, and septic tanks or sewers.

Question: how much water would be "too much" water to be flushed into a septic system

"Water in large quantities"

What would be a "large quantity"?
1 gallon? 2 gallons? Swimming pool? - Tim

Reply: Water volumes that exceed the design load for septic system - x gallons/day

Tim,

About "how much water is too much for a septic system to handle?", let's be reasonable. Posed by your question, a gallon of water would hardly be a "large" quantity since that's less than some toilet flushes. And a bath tub or shower use typically consume 30-50 gallons of water. A typical home septic system is designed to accept a daily wastewater load of 100-200 gallons per person in a household.

What can flood a septic drainfield and/or even damage a septic effluent dosing system are water volumes that exceed the anticipated daily design load. Examples of "large quantities of water" that damage septic system are most often found where equipment is malfunctioning:

- a water softener stuck in "regen" cycle can pump water continuously into the septic system, hundreds of gallons a day added to the normal load

- leaky toilets and other fixtures might, depending on flow rate, also flood the system

- putting together a local laundromat and connecting it to a typical residential septic system would flood and overload the system

- failing to keep groundwater away from the septic tank or drainfield flood the system and lead to its failure.

About a swimming pool, I'm doubtful that anyone would try emptying a swimming pool into a septic system, but indeed, I have seen failed drainfields that were saturated when a homeowner repeatedly emptied pool filter backwash waters and annual swimming pool drain-out waters directly onto the septic drainfield or soakaway bed.

Thanks for asking - these are important clarifications.

Question: What's the difference between "never flush" and "better not flush" categories of building drain and septic system care warnings?

Why are some of these items "never" and others "better not". I don't understand the distinction?

Also, why did deepesh ask about flushing toys down the toilet? Deepesh, do you really have no other way of disposing of them?

- Randy

Reply: Definition of "never flush" and "better not flush" drain dumping and septic system protection categories

Randy: good question. Thanks for asking for this clarification on the difference between NEVER FLUSH and BETTER NOT FLUSH things into a septic tank.

What's in the "Never-Flush-into-Septic" category?

Having researched various expert sources on septic tank and system care as well as having investigated septic system failures, in my OPINION some materials are very harmful and likely to cause costly damage if flushed down drains and into septic tanks and drainfields, while others may also contaminate groundwater, nearby wells, and the environment. Those items go into the NEVER FLUSH INTO SEPTICS category of things to keep out of drains and septic systems.

What's in the "Better-Not-to-Flush-into-Septic" category?

Other items, like cigarette butts, do not biodegrade in the septic tank, and can possibly contribute mass to a clog or blockage in a drain, but their individual size and anticipated plausible volume of occurrence in a septic tank is so small as unlikely to actually damage the tank. Rather they add non-biodegradable mass that has to be removed when the tank is pumped. These are a bad idea - they risk remaining in the waste chain, even being spread in sludge on a field somewhere where they still don't biodegrade - but as their probability of causing rapid or expensive damage to the septic system is much less or even nil, I put these into the BETTER NOT TO FLUSH category.

At TOILETS, DON'T FLUSH LIST our summary page for this topic, and among the links listed at Related Topics under that heading, you'll see a series of articles that explain the hazards of dumping or spilling various materials into drains and into septic systems.

Question: Are toilet tank cleaners that clean with every flush bad for the septic system?

How about those toilet tank cleaners that clean with every flush, especially with bleach.

I have a septic system 4 years old now, and since day one i use blue bowel flush cleaners with bleach.

This year for the first time i noticed there is no grass on leach field. Is this my problem and should i stop using toilet tank flush cleaners. Please advise. Thanks - Dave A 4/21/11

Reply: Content, properties, & uses of some common toilet tank cleaners, deodorizers, & treatments

Dave,

The amount of bleach from a typical toilet tank solid cleaner-insert cake in normal usage should not produce enough bleach in the septic tank to have a noticeable effect on the tank bacteria.

We found that toilet tank deodorant or "cleaner" product ingredients varied by product; some of the typical ingredients listed (not all of these are present in every product) included:

Ascorbic Acid (preservative)
Borax
Fragrances
Salts of bisulfate
Surfactants
Sodium sulfate
Thickeners
Trichloroisocyanurate of sodium
Color agents and dyes

Watch out: most of the toilet tank deodorizer and treatment tablets and products we surveyed (October 2012) include

warnings to keep these products out of reach of children
warning to use plastic or rubber gloves when handling the product
warning to avoid mixing these products with others that contain ammonia or bleach (dangerous or toxic gas reactions can result)
warning that in case of skin or eye contact, because burns are possible, wash with plenty of clean water

Watch out: I found in testing about 15 years ago that some toilet tank treatments caused the flush valve to deteriorate, resulting in running toilets that did flood the drainfield.

There is research on the effects of treatments for RV holding tanks and septic systems (a concern for those emptying an RV wastewater holding tank into a residential septic tank) and for toilet and toilet tank deodorants:

I will post some citations above at Chemical Contaminants Found in Residential Wastewater & Their Sources

Question:

Is bleach from a washing machine safe for a septic system? How much? - Alan 10/5/12

Reply:

Alan,

Bleach used at normal levels in a home laundry system should be so dilute in the septic tank as not to cause a problem. Follow the manufacturer's instructions;

Watch out: I would agree that dumping bleach wholesale into building drains for any reason is not a good idea and could damage the septic system. In fact in a separate article on cheating on water quality testing, we report observations including by Steve Vermilye (dec). that property owners who had sanitized a well with high doses of bleach right before a building inspection put enough bleach into the water supply that we could observe the septic dye test colorizing dye fading from red to clear as the dyed water entered the septic tank.

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Questions & answers or comments about what things harm the septic system if flushed down toilets or other building drains

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Technical Reviewers & References

Related Topics, found near the top of this page suggest articles closely related to this one.

"Save the Septic System - Do Not Flush These Items Down the Toilet", Daniel Friedman, InspectAPedia.com - PDF document, printable reference card
Additives & Chemicals: Septic System Maintenance - Are they even needed? Are they even legal?
Biomat Formation in the Septic System Drainfield Absorption System - what leads to drain field clogging and expensive drainfield repairs
Buyer's Guide to Septic Systems - what to do when buying a home with a septic tank
Cesspools Home Buyer's or Owner's Advice
Cheating on Water Tests - (Chlorine in Wells and Septics) Testing Water for Real Estate Transactions - Water Test Cheating Warnings for Home Buyers and Home Inspectors
Clogged Drain Diagnosis - is the problem the septic system or the Building drain system?
DRYWELL DESIGN & USES Home Buyer's or Owner's Advice
Contamination in buildings how to test buildings for bacterial contamination from Sewage and Septic backup, remediation, & references
Leach Field Inspection Procedure Septic Leach Fields - how to inspect and diagnose septic drainfield failures - what causes septic field failure?
Maintenance: Ten Steps to Keeping a Septic System Working, suggestions from the U.S. EPA, edits and additions by DJF
Septic Systems Inspection, Testing, & Maintenance Book - online textbook: how to inspect, maintain, repair septics
Septic Tank Pumping Guide: When, Why, How to pump the septic tank
Septic Tank Location - How to Find the Septic Tank, how deep will the cover be, how to document its location
Sewage Pump Clog Damage - list of items that clog and damage or destroy different types of sewage pumps, grinder pumps, and ejector pumps
Sewage & Septic Backups and what to do about sewage spillage in buildings
Tank Location - How to Find the Septic Tank, how deep will the cover be, how to document its location
Tank Pumping Frequency Guide for Septic Tanks: When, How, What to Watch For when pumping or cleaning septic tanks
Water Usage: Capacity: Determining Needed Septic Capacity - Typical residential water usage for people, appliances, and activities.
Watts Industries of North Andover, Mass., provides its ZRO-4 under counter system intended to target the independent water dealer market.

What is a Septic System An Engineer's View & Septic System FAQ's

...

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 Pumping Guide: When, Why, How to pump the septic tank
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.
Septic System Drainfield Absorption System Biomat Formation - what leads to drain field clogging and expensive drainfield repairs
Ten Steps to Keeping a Septic System Working, suggestions from the U.S. EPA, edits and additions by DJF
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.

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. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.

Or choose the The Home Reference eBook for PCs, Macs, Kindle, iPad, iPhone, or Android Smart Phones. Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter INSPECTAEHRB in the order payment page "Promo/Redemption" space.

Building inspection education & report writing systems from Carson, Dunlop & Associates Ltd

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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