Septic systems are used to treat and dispose of relatively small volumes of wastewater, usually from houses and businesses that are located relatively close together. Septic systems are also called onsite wastewater treatment systems, decentralized wastewater treatment systems, on-lot systems, individual sewage disposal systems, cluster systems, package plants, and private sewage systems.

How do septic systems work?

The typical septic treatment system includes a septic tank, which digests organic matter and separates floatable matter (e.g., oils and grease) and settle-able solids from the wastewater. Soil-based systems discharge the liquid (effluent) from the septic tank into a series of perforated pipes buried in a leach field, leaching chambers, or other special units designed to slowly release the effluent into the soil or surface water.

Alternative systems use pumps or gravity to help septic tank effluent trickle through sand, organic matter (e.g., peat, sawdust), constructed wetlands, or other media to remove or neutralize pollutants like disease-causing pathogens, nitrogen, phosphorus, and other contaminants. Some alternative systems are designed to evaporate wastewater or disinfect it before it is discharged to the soil or surface waters.

Why do septic systems fail?

Most septic system failures are related to inappropriate design and poor maintenance. Some soil-based systems (with a leach or drain field) have been installed at sites with inadequate or inappropriate soils, excessive slopes or high ground water tables. These conditions can cause hydraulic failures and water resource contamination. Failure to perform routine maintenance, such as pumping the septic tank at least every 3 to 5 years, can cause solids in the tank to migrate into the drain field and clog the system.

What items should not be put down the drain if my house has a septic system?

Do not put the following items into sink drains or toilets: hair combings, coffee grounds, dental floss, disposable diapers, kitty litter, feminine hygiene products, cigarette butts, condoms, gauze bandages, fat, grease, oil, paper towels, paints, varnishes, thinners, waste oils, photographic solutions or pesticides.

What should I do if my basement floods?

If sewage from your plumbing fixtures or onsite system backs up into your basement, avoid contact with the sewage and the possibly harmful pathogens it might contain. Contact your local health department or regulatory agency. Cleanup personnel should wear protective clothing (e.g., long rubber gloves, face splash shields). After cleanup is complete, all equipment, tools, and clothing used in the cleanup and the flooded basement area should be washed thoroughly and disinfected with a mixture of 90 percent water and 10 percent household bleach. The area should be dried out with fans, heat lamps, or other devices and not be used until it has been completely dry for at least 24 hours.

– Courtesy of the Environmental Protection Agency.