Onsite Wastewater Treatment / Septic


SepticSeptic systems are used to treat and dispose of small volumes of wastewater onsite, usually from houses and businesses located in suburban and rural locations not served by a centralized public sewer system. Septic systems treat wastewater from household plumbing fixtures (toilet, shower, laundry, etc.) through both natural and technological processes.

Septic systems are also called:

  • onsite wastewater treatment systems,
  • decentralized wastewater treatment systems,
  • cluster systems,
  • package plants,
  • on-lot systems,
  • individual sewage disposal systems, and
  • private sewage systems.

Onsite wastewater treatment systems (septic systems) have the potential to contaminate groundwater and surface water resources, including drinking water supplies, with nitrates and other nutrients, chemicals, pathogens, and pharmaceuticals. However, when properly located, designed, constructed, and maintained, septic systems provide an effective and efficient means of treating domestic sewage and protecting water quality. Furthermore, there are economic and ecological advantages to managing wastewater within the watershed where it is produced.

Thousands of unsewered communities and rural residences will continue to depend on onsite systems for wastewater treatment and disposal. Today, as the population migrates farther from metropolitan areas, about one-third of all new development is served by decentralized treatment systems (USEPA, 2004). Onsite systems allow communities to develop while providing them with the means for adequately handling wastewater. To minimize the impacts of these systems on ground water, we need to:

  • Ensure that onsite systems are properly designed, installed, and maintained.
  • Take full advantage of innovative designs and sound science.
  • Adopt effective management solutions.
  • Actively educate the public on what wastes should not be put into their systems, and how these systems should be maintained.

From the Ground Water Report to the Nation

Onsite Wastewater Treatment Systems - Summary Sheet : Full Chapter

Additional Resources


Op Ed: Decentralized Wastewater Infrastructure - Challenges and Opportunities

This Op-Ed was created as a part of SepticSmart Week - an annual event focused on educating homeowne...

GWPC Proclaims Septic Smart Week September 14-18, 2020

This annual event, organized by the US EPA's Decentralized Wastewater Management MOU Partnership, is...

GWPC Supports Septic Smart Week

This week is Septic Smart Week! The Ground Water Protection Council (GWPC), a member of the EPA Dece...


09/12/2023 – 09/14/2023
Tampa, Florida, Westshore Grand Hotel

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Ground Water Report to the Nation

Our groundwater resources are in serious need of attention. Abundant, high quality, low-cost groundwater resources are fundamental to the long-term growth and vitality of our nation, yet this most important resource is often overlooked, if not neglected. Attention to the protection and management of groundwater has consistently lagged behind that given to surface waters, meaning that historic and current water resource laws and policies deal primarily with the protection and management of our more visible lakes, rivers, and wetlands.The purpose of the Ground Water Report to the Nation is to highlight some of the more prevalent threats to groundwater, share sucess stories, and make recommendations for improved groundwater protection and awareness.  Note: Please visit the Ground Water Report to the Nation topics page for individual chapters of the report.

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Comments on EPA’s Draft National Water Program Guidance 2018-2019, Publication Number 800D17001

The Ground Water Protection Council (GWPC) provided comments on the draft National Water Program Guidance for 2018-2019.