When a public sewer system isn’t available, homes and businesses often use septic systems to handle the household’s used water and waste. In these cases, the building’s plumbing isn’t much different, but the waste is handled on-site with septic systems that require regular septic pumping and septic tank maintenance.

All of the water and waste leaves the building from a central pipe that takes it out to the septic tank. This includes sewage from the toilets, as well as water from baths, sinks, and kitchen use. The tanks may have a single compartment or two compartments that are used in sequence. When the waste and water flows in through the “inlet” of the tank, the “baffle” helps push it down into the tank, so it doesn’t settle on top. Eventually, the solids settle on the bottom of the septic tank, in a layer called “sludge,” while another layer of things like fats and toilet paper float to the top. This is called “scum.” The material in the middle, called “effluent,” is safe to leave the septic tank through the “outlet” where it’s dispersed into an absorption area, often referred to as a “leach field.”

There are a lot of different types of setups for what happens to the effluent when it leaves the septic tank. The area may be referred to as a leach field, drain field, septic field, septic drain field, septic tank drainfield, or septic leach field, but the concept is generally the same with these. The effluent isn’t quite clean yet, and so it’s carried through a series of pipes beneath the soil. The pipes have lots of holes, allowing the effluent can seep out. Any organic material in it is digested by the bacteria that naturally lives in the top layers of soil. A leach field is probably the most common setup, though there are also graywater recycling systems that can be hooked up, and some older homes also use a “soak pit,” which is essentially a hole filled with rocks or gravel.

Understandably, the layers of sludge and scum tend to build up, so septic systems and their pipes need to be cleaned regularly. Most of the time, a 3-5 year schedule is recommended, to keep the system running optimally, but the time may increase if the home has a garbage disposal or if a lot of people are contributing to filling the tank.