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How to maintain your septic system

Septic systems are a very simple way to treat household wastewater and are easy to operate and maintain. Although homeowners must take a more active role in maintaining septic systems, once they learn how their systems work, it is easy for them to appreciate the importance of a few sound operation and maintenance practices.

What makes up a Septic System?

There are two main parts to the basic septic system: the septic tank and the drainfleld.

The Septic Tank

Household wastewater first flows into the septic tank where it should stay for at least a day. In the tank, heavy solids in the wastewater settle to the bottom forming a layer of sludge, and grease and light solids float to the top forming a layer of scum (refer to the graphic on next page).

The sludge and scum remain in the tank where naturally occurring bacteria cannot completely break down all of the sludge and scum, however, and this is why septic tanks need to be pumped periodically. The separated wastewater in the middle layer of the tank is pushed out into the drainfield as more wastewater enters the septic tank from the house. If too much water is flushed into the septic tank In a short period of time, the wastewater flows out of the tank before it has time to separate.

 representation of a typical septic tank

This can happen on days when water use is unusually high (laundry day, for example), or more often if the septic tank is too small for the needs of the household. Some septic tanks are outfitted with a baffle screen. This screen serves to protect the drain field from receiving solids.

The Drainfield

When wastewater leaves a septic tank too soon, solids can be carried with it to the drainfield. Drainfields provide additional treatment for the wastewater by allowing it to trickle from a series of perforated pipes, through a layer of gravel, and down through the soil. The soil acts as a natural filter and contains organisms that help treat the waste. Solids damage the drainfield by clogging the small holes in the drainfield pipes and help to create a clogging mat in the surrounding gravel, and excess water strains the system unnecessarily.

How to Care For Your Septic System

Septic system maintenance is often compared to automobile maintenance because only a little effort on a regular basis can save a lot of money and significantly prolong the life of the system.

Sound septic system operation and maintenance practices include conserving water, being careful that nothing harmful is disposed of through the system, and having the system inspected annually and pumped regularly.

By educating everyone in your household about what is and what isn’t good for septic systems, they can begin to develop good maintenance habits.

Use Water Wisely

Water conservation is very important for septic systems because continual saturation of the soil in the drainfield can affect the quality of the soil and its ability to naturally remove toxins, bacteria, viruses, and other pollutants from the wastewater.

The most effective way to conserve water around the house is to first take stock of how it is being wasted. Immediately repair any leaking faucets or running toilets, and use washing machines and dishwashers only when full.

In a typical household, most of the water used indoors is used in the bathroom, and there are a lot of little things that can be done to conserve water there.

For example, try to avoid letting water run while washing hands and brushing teeth. Avoid taking long showers and install water-saving features in faucets and shower heads. These devices can reduce water use by up to 50 percent. Low-flush toilets use one to two gallons per flush compared to the three to five gallons used by conventional toilets.

Pie chart of typical household water usage

Even using a toilet dam or putting a container filled with rocks in the toilet tank can reduce water use by 25 percent.

It is also important to avoid overtaxing your system by using a lot of water in a short time period, or by allowing too much outside water to reach the drainfield. Try to space out activities requiring heavy water use (like laundry) over several days. Also, divert roof drains, surface water, and sump pumps away from the drainfield.

Know What Not To Flush


What you put into your septic system greatly affects its ability to do its job. As a general rule of thumb, do not dispose of anything in your septic system that can just as easily be put in the trash. Remember that your system is not designed to be a garbage disposal, and that solids build up in the septic tank and eventually need to be pumped out.

In the kitchen, avoid washing food scraps, coffee grounds, and other food items down the drain. Grease and cooking oils contribute to the layer of scum in the tank and also should not be put down the drain. Garbage disposal can increase the amount of solids in the tank up to 50 percent and are not recommended for use with septic systems.

The same common-sense approach used in the kitchen should be used in the bathroom. Don’t use the toilet to dispose of plastics, paper towels, tampons, disposable diapers, condoms, kitty litter, etc. The only things that should be flushed down the toilet are wastewater and toilet paper. (For a list of items, see “Do Not Flush” later in this guide).

Avoid Hazardous Chemicals

To avoid disrupting or permanently damaging your septic system, do not use it to dispose of hazardous household chemicals. Even small amounts of paints, varnishes, thinners, waste oil, photographic solutions, pesticides, and other organic chemicals can destroy helpful bacteria and the biological digestion taking place within your system. These chemicals also pollute the groundwater.

Some septic system additives that claim to help or clean your system also contain hazardous chemicals and should be avoided. (See the Q&A on septic system additives following this section).

Household cleaners, such as bleach, disinfectants, and drain and toilet bowl cleaners should be used in moderation and only in accordance with product labels. Overuse of these products can harm your system. It makes sense to try to keep all toxic and hazardous chemicals out of your septic tank system when possible.

To help prevent groundwater pollution, be sure to dispose of leftover hazardous chemicals by taking them to an approved hazardous waste collection center. For locations and more information, contact your local health department.

Pump Your Tank Regularly

Pumping your septic tank is probably the single most important thing you can do to protect your system. If the buildup of solids in the tank becomes too high and solids move to the drainfield, this could clog and strain the system to the point where a new drainfield will be needed.

Inspect Your System Annually

Inspection your septic system annually is a good way to monitor your system’s health. Inspections can reveal problems before they become serious, and by checking the levels of sludge and scum in your tank, you can get a more accurate idea of how often it should be pumped. For a more detailed discussion of septic system inspections and recommended pumping frequencies and procedures, read the section “Pumping and Inspecting Your System, What To Expect” later in this guide.

Protect Your System

Finally, it is important to protect your septic system from potential damage. Don’t plant anything but grass near your septic system, roots from shrubs and trees can cause damage, and don’t allow anyone to drive or operate heavy machinery over any part of the system. Also, don’t build anything over the drainfield. Grass is the most appropriate cover for the drainfield.


Q. Do I need to add anything to my septic system to keep it working properly?

A. While many products on the market claim to help septic systems work better, the truth is there is no magic potion to cure an ailing system. In fact, most engineers and sanitation professionals believe that commercial septic system additives are, at best, useless, and at worst, potentially harmful to a system.

There are two types of septic system additives: biological (like bacteria, enzymes, and yeast) and chemical. Most biological additives are harmless, but some chemical additives can potentially harm the soil in the drainfield and contaminate the groundwater.

While there hasn’t been extensive study on the effectiveness of these products, the general consensus among septic system experts is that septic system additives are unnecessary.

Q. What type of toilet paper is best for septic tanks?

A. Contrary to popular belief, it is not necessary to sacrifice personal comfort to protect your septic tank. There are many types of toilet paper on the market that are perfectly safe for septic system.

According to the National Sanitation Foundation (NSF), a nonprofit organization that tests products relating to health and the environment, the thickness and color of toilet tissue does not necessarily affect its biodegradability.

NSF subjects the toilet papers it certifies to rigorous testing, and the brands that pass carry the NSF mark stating that they are safe for use with septic systems. However, there probably are many brands without the NSF mark that are also safe.

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