About Septic Systems
More than one in five households in the U.S. depend on individual septic (decentralized) systems or small community cluster systems to treat their wastewater. These systems are used to treat and disperse of relatively small volumes of wastewater, usually from houses and businesses located in suburban and rural locations not served by a public (centralized) sewer system.
Septic systems are underground wastewater treatment structures that use a combination of natural and technological processes to treat wastewater from household plumbing produced by bathrooms, showers, kitchen drains and laundry. The process typically begins with solids settling within the septic tank and ends with wastewater treatment in the soil via the drainfield.
Septic systems are also called:
- decentralized wastewater treatment systems,
- onsite wastewater treatment systems,
- cluster systems,
- package plants,
- on-lot systems,
- individual sewage disposal systems, and
- private sewage systems.
There are various types of septic or decentralized wastewater treatment systems. If a system is properly installed, sited and maintained it can protect public health, preserve valuable water resources, and maintain economic vitality in a community. Decentralized systems are a cost-effective and long-term option for treating wastewater, particularly in less densely populated areas.
The benefits of using decentralized wastewater treatment systems include:
- Public health benefits - Proper use of decentralized systems reduces the risk of disease transmission and human exposure to pathogens, which can occur through drinking water, surface water and shellfish bed contamination.
- Environmental benefits - Wastewater treatment removes pollution from surface water, recharges groundwater and replenishes aquifers.
- Economic benefits - Decentralized wastewater systems help communities reduce large infrastructure and energy costs to collect and treat wastewater.
EPA’s Glossary of Septic System Terminology contains terms commonly used in the wastewater treatment field and their definitions.