Septic Tank Cleaning: Bacteria Levels In Your Septic Tank

Approximately 25% of all U.S. households rely on independently owned septic tanks for the removal of waste. Septic tanks are efficient and effective; however, they do not need to be maintained properly in order to have a long lifespan. Most experts recommend pumping or cleaning septic tanks at least once every three years. When cleaning the septic tanks, you are essentially disrupting the small ecosystem of anaerobic bacteria that are residing within the tanks and responsible for degrading all organic compounds. As a result, it is important to know how to preserve bacteria levels in your septic tank even when you are cleaning.

Use Appropriate Cleaning Agents

Although septic tanks may seem filthy, never use antibiotics or even harsh cleaners, like detergents, to clean them, as this will disrupt and kill off the bacteria living within the tanks. Studies have shown that approximately 2 gallons of bleach is sufficient in harming the bacteria that reside within a static septic tank. Hydrogen peroxide and other chemicals are also quite harmful. It is important that you either pump the septic tanks clean or use organic cleaners that do not disrupt the ecosystem of bacteria; otherwise, the septic tanks will no longer be efficient nor effective in waste removal.

Measure the Amount of Bacteria Present

When cleaning the septic tanks, you want to make sure that the amount of bacteria present is at an appropriate level. Measuring the sludge and scum that has accumulated within the tanks can provide better insight into this issue. When collecting sludge and scum, never lean into the septic tanks, as you could easily become poisoned or asphyxiated from the gas that is being released. The sludge and scum measurements can tell you whether the tanks need to be cleaned and whether the bacteria have been doing their job.

Add Starter Bacteria

If you believe that the bacteria levels in your septic tank are relatively low, then add starter bacteria that can be purchased in stores. After the first time that the toilet is flushed, the bacteria from the starter pack will begin to inoculate within the septic tanks. Simply pour the starter bacteria into the septic tanks, and let them do their job.


When cleaning your septic tanks, make sure that you do not disrupt the role of the bacteria within them. Millions of bacteria are responsible for decomposing the waste. Unsaturated soils surrounding the septic tanks also contain aerobic bacteria that are responsible for destroying pathogens. At times, experts will also measure the levels of these bacteria as well in order to make sure that harmful pathogens do not enter the surrounding environment. Read more about septic tanks at your local expert's office or website.