a home photo lab - lots of photo chemicals into the septic system might be a problem at this propertyDoes a home Washing Machine Affect the Septic Tank?

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Clothes washing machines vs. the septic system:

Can we use a clothes washer or "washing machine" when a home is connected to a private septic system? What steps should be taken to protect the septic system from excessive water use or clothes lint or detergents? How to extend the life of a septic system.

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Washing Machine Draining into Septic System

washing machine and various household chemicals and cleaners

Article Contents

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Does a washing machine overload and harm the septic system?

The volume of water from home washing machine use should not be a problem with a normal septic system in good working order.

As we discussed at Dishwashers, in some conditions you should avoid emptying washing machine discharge into the septic system:

Below we discuss steps you can take to minimize the possible effects of extra wastewater loads caused by washing machines, and then we discuss the effects of detergents and soaps when operating a clothes washer connected to a septic system or drywell.

Does Washing Machine Detergent Harm the Septic Tank or Septic System Drainfield?

The volume of detergent from a residential clothes washer entering the septic system is so low as to be very dilute when it enters the septic tank, dilute enough that it is not going to harm the septic tank bacteria at normal levels of residential dishwasher use.

Clothes washing machine detergents do not make a high level of suds inside the machine.They rely on surfactants, high water temperature, and time spent agitating the contents of the clothes washing machine to clean them.

However many if not most washing machine (and dishwasher) detergents contain phosphates or nonylphenol ethoxylate surfactants. Surfactants are what make detergents effective in lifting soil particles off of a surface (a dish in the dishwasher or a shirt in the washing machine). These chemicals may be serious contaminants of ground water and surface water in the environment.

What laundry detergents or soaps should we use in a Clothes Washing Machine connected to a septic tank or to a Graywater System?

washing machine and various household chemicals and cleaners

Sometimes we find that dry powder clothes washer soap appears as clots and clogs in the system - usually because the homeowner is pouring in too much detergent and is not following the manufacturer's instructions.

Passing solid clumps of detergent into the septic tank speed clogging of the system and in severe cases can even block a building drain.

Recommended dishwasher & laundry detergents: are discussed in detail separately

at DETERGENTS in our article

at DISHWASHERS vs SEPTICS where we discuss recommended detergents and also the effects of phosphates & detergents on the environment.

How to minimize the possible clogging or other effects of laundry soaps on the septic system

Apartment building washing machine room (C) Daniel Friedman

A private septic system tank and drainfield can be protected from clogging due to excessive use of detergents.

And even if a building's wastewater is carried to a public sewer there may be concerns with detergent clogging in the drain system. In the laundry room serving a residential apartment building such as shown in our photo (left, Bronx, NY), asking residents to follow these suggestions can help prevent sewer drain clogging.

The following measures may relieve the water volume load on septic fields from the washing machine:

photo of a graywater filter for septic systems


& CHEMICALS to KEEP OUT OF SEPTICS - separate articles

Effects of Household Bleach on the Septic System

Bleach at normal household usage levels should not harm the septic system.


Continue reading at WATER SOFTENER IMPACT on SEPTIC or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see WASHING MACHINES & SEPTIC SYSTEMS FAQs - questions & answers posted originally at the end of this page.

Or see these

Don't Flush Articles for Sewage Grinder Pumps, Toilets, Septic Systems, Drains

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WASHING MACHINES & SEPTIC SYSTEMS at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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Publisher - Daniel Friedman