Can You Use a Garbage Disposer with a Septic Tank?

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InSinkErator Evolution Septic Assist product photo
InSinkErator Evolution Septic Assist

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Waste King L-8000

Septic Tank Safe Garbage Disposal Guide

Last updated February 6th, 2020

Almost 1/5 of homes in the USA are connected to a septic tank system with rural homes the least likely to be connected to a public sewer system. Many of these homeowners are confused about the conflicting advice on whether garbage disposals are bad for septic tanks and whether you need a special garbage disposal for septic systems.

This article will answer these questions and help you decide whether installing a garbage disposer is right for you.

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Are Garbage Disposers Safe for Septic Tanks?

The simple answer to “can I have a garbage disposal with a septic tank?” is yes!

However, before you go out and buy a waste disposer there are a few things that you need to be aware of.

Septic tank safe garbage disposer installed under sink

Fitting the wrong garbage disposer can put a strain on your septic system so make sure you read this page and the waste disposal buying guide before making a purchase.

Septic tanks are very sensitive to what you flush into your waste water and some food waste items are not suitable.

Many septic tank owners opt to install a waste disposal unit without problems or additional septic tank pumping.

However, it’s good to remember that septic tanks are much more sensitive to what you flush into your waste water and that some food waste items are not suitable and will cause problems.

If you treat your garbage disposer like a bin then you will end up causing problems in the future.

Some food waste will not be broken down by your septic tank and some items like rice and pasta will even expand when the enter the system causing blockages.

Garbage Disposers & Septic Tank Bacteria

One of the main arguments of whether garbage disposers are safe to use with septic tanks is the bacteria problem.

The bacterial culture inside a septic tank is finely balanced and a critical part of the waste water treatment process.

Overloading a septic tank with too much organic matter can disrupt the delicate bacteria levels causing food waste to accumulate and eventually block the tank requiring regular pumping and repairs to your septic system.

Septic tank under construction

One way to overcome this is by using special enzyme additives. Usually this requires you to add them directly into the septic tank.

Some garbage disposal manufacturers like InSinkErator have a unique solution to this by injecting the enzymes directly into your septic tank every time food waste passes through the disposer.

The bacterial culture inside your septic tank is finely balanced & a critical part of your waste water treatment.

If you are worried about your waste disposal unit harming the bacteria levels check out our recommended garbage disposers for septic tanks.

Buying Guide

What can you put down a garbage disposal with a septic tank?

Small food scraps that end up in your sink are fine to put through the garbage disposer as they will be broken down efficiently by the grinding chamber.

Once in the septic tank they will be further broken down by your tank’s bacteria.


  • Small food scraps
  • Dishwasher outlet

Don’t use your garbage disposers like a trash can. Some types of food won’t break down in your septic tank and will accumulate.

Did you know? Connecting your dishwasher outlet to your waste disposer is an effective way of ensuring any food scraps that flow from your dishwasher are broken down.

What not to put in a garbage disposal with a septic tank

Remember not to use your waste disposal unit like a trash can.

Some types of food waste as well as fats and oils will struggle to break down in your septic tank and will eventually accumulate, causing blockages and requiring more regular pumping.

Photo of dirty cooking oil

Putting too much organic matter into your septic tank will also alter the finely tuned bacteria levels in your tank making it less effective at treating your waste water.


  • Cooking oils, fat, grease
    A septic tank will be unable to break these down effectively causing them to solidify and float to the surface of the tank causing problems.
  • Non-food items
    These will not be broken down effectively and will alter your tanks bacteria levels.
  • Fibrous vegetables
    Low-end garbage disposers struggle to grind down stringy/fibrous foods like celery causing them to accumulate and block your septic system.
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The Best Garbage Disposer for Septic Tanks

InSinkErator Evolution Septic Assist

Photo of InSinkErator Evolution Septic Assist

The safest option for households with septic tanks

The Evolution with Septic Assist has been designed to use safely with a septic system. Its Biocharge injection system breaks down food particles even further to prevent blockages.


  • 3/4 Horsepower
  • 1725 RPM motor
  • Bio-charge septic assist enzymes
  • Built in the USA
  • 2-stage grind chamber
  • Stainless steel grind chamber & components
  • SoundSeal noise dampening
  • 4-year in-home warranty


  • Power cord sold seperately
  • Issues with Bio-Charge bottle coming loose/leaking
  • Bio-Charge injection system not repairable
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The Best Budget Garbage Disposer for Septic Tanks

Waste King L-8000

Photo of Waste King L-8000 Waste Disposal

A powerful disposer for septic systems that’s great value for money

The high-powered L-8000 uses a 1HP motor to efficiently break down food waste particles. The Waste King is a great qualty, septic-safe waste disposer & perfect for households on a budget.


  • 1 Horsepower 2800 RPM motor
  • Stainless steel blade
  • 20-year warranty
  • Corrosion resistant grinding chamber
  • Power cord included


  • Some report issues with leaking
  • Takes up a lot of space under the sink


Septic tank photo by SuSanA Secretariat