• Septic tank
• Drainfield (leachfield)
• Inlet and outlet pipes
• Soil

A septic tank is a large underground container made of concrete, fiberglass, or plastic. It is responsible for holding and treating wastewater from a property. However, not all people with septic systems understand how a septic tank works. Knowing how a septic tank works allows you to implement proper maintenance practices. Read on to learn more about how a septic tank works and how to keep your septic tank in tip-top shape.

How Does a Septic Tank Work?

All the wastewater from toilets, sinks, showers, and other drains in the property flows into the septic tank through an inlet pipe. Once the wastewater is collected inside the tank, it undergoes a separation process. The waste is separated into three layers—sludge, scum, and effluent.

• Sludge is the heavy organic and inorganic material that settles to the bottom of the tank.
• Scum comprises lighter substances like oil, grease, soaps, and toilet paper that float to the top.
• The middle layer, known as effluent, comprises water, other liquids, and suspended solids.

The septic tank provides an oxygen-deprived environment, ideal for anaerobic bacteria to thrive. These bacteria naturally occur in the wastewater and begin the process of anaerobic digestion. They break down the organic solids in the sludge and scum layers into simpler compounds through chemical reactions, reducing their volume over time.

As new wastewater enters the tank, an equal amount of treated effluent flows out of the tank through an outlet pipe. The effluent is relatively clear and contains fewer solids compared to the original wastewater. The effluent exits the septic tank and flows into a drainfield or leachfield, where further treatment occurs. In the drainfield, the effluent percolates through perforated pipes and into the surrounding soil. The soil acts as a natural filter, removing remaining impurities and harmful bacteria.