Maintaining Your Septic System 

Out of sight and out of mind – does this describe your relationship with your septic system? If you are like most homeowners, you probably never give much thought to what happens to what goes down your drain. But if you rely on a septic system to treat and dispose of your household wastewater, what you don’t know can hurt you. Proper operation and maintenance of your septic system can have a significant impact on how well it works and how long it lasts, and in most communities, septic system maintenance is the responsibility of the homeowner. This fact sheet was written as one in a series to help septic system owners maintain their septic systems.

Why Maintain Your System?

There are three main reasons why septic system maintenance is so important. The first reason is money. Failing septic systems are expensive to repair or replace, and poor maintenance is a common cause of early system failures. The minimal amount of preventative maintenance that septic systems require, costs very little in comparison. For example, it typically costs from $3,000 to $10,000 to replace a failing septic system with a new one, compared to approximately $50 to $150 to have a septic system inspected, and $150 to $250 to have it pumped.

The second and most important reason to maintain your system is to protect the health of your family, your community, and the environment. When septic systems fail, inadequately treated household wastewater is released into the environment. Any contact with untreated human waste can pose significant health risks, and untreated wastewater from failing septic systems can contaminate nearby wells, groundwater, and drinking water sources. Chemicals improperly released through a septic system also can pollute local water sources and can contribute to system failures. For this reason it is important for homeowners to educate themselves about what should and should not be disposed of through a septic system.

Finally, the third reason to maintain your septic system is to protect the economic health of your community. Failed septic systems can cause property values to decline. Sometimes building permits cannot be issued or real estate sales can be delayed for these properties until systems are repaired or replaced. Also, failed septic systems can contribute to the pollution of local rivers, lakes. and shorelines that your community uses for commercial or recreational activities.

Inspecting Your System 

Annual inspections of your septic system are recommended to ensure that it is working properly and to determine when the septic tank should be pumped. By inspecting and pumping your system regularly, you can prevent the high cost of septic system failure. If the sludge depth is equal to one third or more of the liquid depth, the tank should be pumped.

A thorough septic system inspection will include the following steps:

  1. Locating the system – Even a professional may have trouble locating your system if the access to your tank is buried. One way to start looking is to go in your basement and determine the direction the sewer pipe goes out through the wall. Then start probing the soil with a thin metal rod 10 to 15 feet from the foundation. Once your system is found, be sure to keep a map of it on hand to save time on future service visits.
  2. Uncovering the manhole and inspection ports – This may entail some digging in your yard. If they are buried, try to make access to the ports easier for future inspections. Install risers (elevated access covers) if necessary.
  3. Flushing the toilets – This is done to determine if the plumbing going to the system is working correctly.
  4. Measuring the scum and sludge layers – There are two frequently used methods for measuring the sludge and scum layers inside your tank. The contractor may use a hollow clear plastic tube that is pushed through the different layers to the bottom of the tank. When brought back up, the tube retains a sample showing a cross section of the inside of the tank. The layers can also be measured using long wooden sticks or poles. See Arizona Cooperative Extension publication AZl 160: Maintaining Your Septic Tank for detailed instructions. As a general guideline, if the scum layer is within three inches of the bottom of the inlet baffle, the tank should be pumped. If the sludge depth is equal to one third or more of the liquid depth, the tank should be pumped.
  5. Checking the tank and the drainfield – The contractor will check the condition of the baffles or tees, the walls of the tank for cracks, and the drainfield for any signs of failure. If your system includes a distribution box, drop box, or pump, the contractor will check these too.

Properly sited, designed, constructed, and maintained septic systems can provide an efficient and economical wastewater treatment alternative to public sewer systems. While septic systems are designed and installed by licensed professionals to meet the needs of individual sites, homeowners are responsible for the system’s operation and maintenance. There is more information on household septic systems at The University of Arizona Extension publications web page ( pubs).