Your Septic Tank: What You Need To Know

Depending on the number of bedrooms, a septic tank (holding tank) can range in size from 500 to 3,000+ gallons (1000 gallons being average) and is an important part of how septic systems work.

Your septic tank is set up to only allow liquid to pass through to the drain / leach field in order not to clog the small weep holes and dry soil with suspended solids. This task is performed through microbial digestion and separation.

Within your septic tank, denser solids sink to the bottom and form “sludge” while the lighter solids, such as oil and grease, move to the top and form what is known as the “scum layer.”

Between these upper and lower layers should be all liquid. Inside your septic tank there are a series of baffles. These baffles work to keep the scum layer held at the top and the solids pooled at the bottom. That way, only liquid can flow to the outlet pipe. This is called the “process of separation.”

The only other thing you really need to note is that your septic tank turns solids into liquid through the process of “Microbial Digestion.” Sludge and scum is liquefied by natural enzymes and bacteria within your septic tank. This same process is used at municipal waste water treatment plants all throughout the country.

After microbial digestion occurs, all the liquefied sewage flows out of the septic tank and into the leaching area (the drain/leach field).