Septic safe products: a practical list for every room

Septic safe products are ones that either break down quickly in water, like toilet paper, or are used in amounts small enough that they do not kill the bacteria in your tank, like everyday soaps and cleaners. EPA’s rule for the toilet is simple: flush only human waste and toilet paper. Everything else that goes down any drain, including sinks, showers and the washing machine, also ends up in the septic system, so it matters what you use there too.

The good news is that you rarely need special products. Normal household cleaners in normal amounts are fine, according to Nebraska Water at the University of Nebraska-Lincoln. The trouble comes from things that never break down and from harsh chemicals used heavily or dumped down the drain.

Quick list: septic safe vs. not septic safe

Generally safe in normal amounts	Avoid or keep out of drains
Toilet paper that breaks down quickly	Wipes of any kind, including “flushable” ones
Liquid laundry detergent	Paper towels, facial tissues, cotton swabs
Ordinary dish soap and dishwasher detergent at the recommended dose	Cooking grease, oil and fat
Normal amounts of household cleaners, including occasional bleach	Chemical drain openers
Mild cleaners used with more scrubbing and less product	Automatic “every flush” toilet bowl cleaners
Hand soap, shampoo and body wash	Paint, paint thinner, solvents, pesticides, antifreeze, gasoline
	Unused medications
	Diapers, feminine hygiene products, condoms, dental floss
	Cat litter, coffee grounds, cigarette butts
	Chlorinated pool or hot tub water

The “avoid” list comes from EPA, Nebraska Extension and the University of Arizona Extension. The sections below explain the reasons.

Septic safe toilet paper

Any toilet paper that breaks down fast in water is fine for a septic tank. Nebraska Water recommends a simple home test:

1. Put a few squares of toilet paper in a jar with a lid and fill it partway with water.
2. Close the jar and shake it.
3. Look at the paper. It should show signs of breaking apart in less than one minute.

If the sheets stay whole after a minute of shaking, choose a different paper. Paper that breaks down slowly adds to the sludge and scum in your tank, which means more frequent pumping. Penn State Extension lists slowly degradable solids such as toilet paper among the factors that affect how often a tank needs pumping.

What not to flush with a septic tank

EPA’s list of items to never flush includes:

• Cooking grease or oil
• Non-flushable wipes
• Feminine hygiene products
• Condoms
• Dental floss
• Diapers
• Cigarette butts
• Coffee grounds
• Cat litter
• Paper towels
• Pharmaceuticals
• Household chemicals such as gasoline, oil, pesticides, antifreeze and paint or paint thinners
• Photographic solutions

Why “flushable” wipes are still a problem

A label that says “flushable” means the wipe can make it through the toilet trap, not that it breaks down in your tank. Nebraska Extension lists wipes, with no exception for flushable ones, among the things to keep out of the system. Anything that does not break down adds to the solids in your tank, so put wipes in the trash.

Medications

Do not flush unused prescription or over-the-counter medicines. EPA lists pharmaceuticals among the items never to flush, and the University of Arizona Extension names antibiotic prescription drugs among products that can harm septic bacteria. Nebraska Water recommends taking unused medications to a household hazardous waste collection instead.

Septic safe cleaners

You do not have to give up cleaning products. The University of Arizona Extension found that normal use of a single cleaning product kills some of the tank’s helpful bacteria, but the population usually recovers quickly. Heavy use is different: excessive amounts can cause “significant and even total destruction of the bacteria population,” and the combined effect of many products used in large amounts can seriously damage the system.

To keep cleaning septic safe, the University of Arizona Extension and Nebraska Water recommend:

• Use the minimum amount of soap, detergent and bleach needed for the job.
• Scrub more and use less cleanser. Mild cleaners work for most jobs.
• Skip automatic toilet bowl cleaners that release bleach or disinfectant with every flush. They put a steady dose of antibacterial chemicals into the tank.
• Treat frequent use of bleach-added detergents as excessive. Occasional bleach in the laundry is fine.
• Use disinfectants sparingly, as Nebraska Extension advises.
• Prevent clogs instead of dissolving them. Keep hair, grease and food scraps out of drains. EPA suggests boiling water or a drain snake rather than chemical drain openers.

Whatever the label says, how much you use and how often matters most.

Laundry detergent and washing machines

Laundry adds a lot of water and lint to a septic system. Nebraska Extension and Nebraska Water recommend:

• Liquid detergent over powder. Powdered detergents can contain fillers that settle as sludge.
• A lint filter on the washing machine discharge. Nebraska Water notes that lint can become scum or sludge in the tank.
• Spreading loads across the week, about one or two a day. EPA warns that doing all the laundry in one day can push wastewater through the tank before it is treated and could flood the drain field.

Are dishwasher pods septic safe?

Used as directed, standard dishwasher pods are generally fine for a septic system. EPA and university extension guidance do not single out dishwasher pods as harmful; their advice is to use detergents in normal, recommended amounts. A few points are worth knowing:

• Phosphate is less of an issue than it used to be. Utah State University Extension notes that since July 2010, Washington and about 16 other states limited phosphate in automatic dishwasher detergent to 0.5%, down from as much as 8.7%.
• Pods are concentrated. Use one pod per load and avoid adding extra detergent. Nebraska Extension’s general advice is to use the minimum amount of soap and detergent needed.
• The pod film is a question mark. Most pods are wrapped in a dissolvable plastic film called polyvinyl alcohol (PVA). An article in Pumper, a septic trade magazine, notes that PVA dissolves but may not fully biodegrade in a septic system. Research on this is still limited. If it concerns you, a powder or liquid dishwasher detergent avoids the film.

Garbage disposals and septic systems

A garbage disposal is not banned in a septic home, but it adds a lot of solids. EPA says food waste builds up as scum and sludge, and if the tank gets full, solids can be pushed into the drain field, clogging pipes. Nebraska Water notes that heavy disposal use can mean pumping about twice as often.

If you have one, use it sparingly. Scrape plates into the trash or a compost bin, never put grease through the disposal, and shorten your pumping interval. Our pumping frequency calculator and guide to how often to pump a septic tank can help you set a schedule.

Water softeners and septic systems

Water softeners regenerate by flushing salty water, called brine, through the system. Research on whether this harms septic systems is mixed, but two university sources give practical guidance:

• Nebraska Extension recommends choosing a demand-initiated softener if you use one. These regenerate based on actual water use instead of a fixed timer, so they discharge less often.
• The University of Minnesota Water Resources Center warns that the large volume of water used to regenerate a softener may push partly treated water out of the tank and into the drain field. It also notes that chloride from the salt cannot be removed in the drain field and ends up in groundwater.

Rules on where softener discharge can go vary by state and county. Ask your local health department or a septic professional before connecting or rerouting a softener line.

Other things to keep out of a septic system

• Pool and hot tub water. The University of Arizona Extension recommends diverting chlorinated pool and hot tub water away from the septic system.
• Paints, solvents and pesticides. Take these to a household hazardous waste collection. Solvents pass through the soil without breaking down and can reach groundwater, according to Kansas State Research and Extension.
• Root killers and septic “cleaners.” Kansas State says root-control chemicals should never be added to a septic system, and EPA does not recommend septic additives. See our guide to septic tank treatment for what the research says.
• Rainwater. EPA advises keeping roof drains and sump pumps away from the drain field, since extra water slows or stops treatment.

Signs something went down the drain that should not have

Slow drains in several fixtures, gurgling, sewage odors or water backing up into a tub or floor drain can mean a clog in the line or a tank that needs attention. A septic professional can pump the tank, check the baffles and filter, and clear the line. If wastewater is coming up into the house, see our septic backup guide and call a licensed pro. Never open the tank and lean in to look, since the gases inside can be deadly.

For more on how the tank handles what you send it, read our full guide to the septic tank.