Septic Systems 101: What Are They and How Do They Work?

If you are accustomed to living in an area with public sewer service, buying a home with a septic system may be unfamiliar. Septic systems are very common on the Mendocino Coast, particularly outside of the city of Fort Bragg and the village of Mendocino.

What is a septic system?

A septic system treats and disperses household wastewater right on the property rather than sending it to a municipal sewer system.

Water from toilets, showers, sinks, washing machines and other household plumbing flows into a buried septic tank.

Inside the tank, heavier solids settle to the bottom, while fats, oils and other lighter materials rise to the top. The liquid wastewater, called effluent, remains between these layers and eventually moves out of the tank for further treatment in the soil.

Where does the water go?

From the septic tank, the effluent travels to a drainfield, sometimes called a leach field.

In a conventional gravity system, the effluent flows through underground pipes into the drainfield. It then gradually filters through the soil, where naturally occurring processes provide additional treatment.

Some properties have systems that cannot rely entirely on gravity. These may include a pump chamber that collects the effluent and periodically pumps it to a drainfield. On the Mendocino Coast, you may also encounter systems designed to distribute effluent into shallower or at-grade drainfields because of the particular soil conditions of the property.

The important thing to remember is that the tank and drainfield work together. The tank separates and holds the solids, while the drainfield and surrounding soil complete much of the wastewater treatment process.

Septic systems don’t need to be intimidating

A properly functioning septic system is simply part of owning many rural homes. The important thing is understanding what type of system a property has, where its components are located, and how it should be maintained.

Next in the series: Conventional septic systems and how they differ from systems that use pumps.

Septic lids

This article provides general information only. Septic systems vary by region, property and design. Buyers and property owners should consult qualified septic professionals and the appropriate local agencies regarding a particular system.