Onsite Wastewater Treatment Systems

Onsite wastewater treatment systems, frequently called decentralized systems, refers to any system used to treat and dispose of/recycle wastewater from homes, businesses, industrial facilities, and sometimes entire communities.

  • Septic systems usually serve up to 20 people, oftentimes individual households or small businesses, and include a septic tank and soil absorption field.
  • The frequency of septic systems varies by region, ranging from ten to over fifty percent of homes in some states.
  • Larger, more complex systems use advanced treatment units which treat and discharge to surface waters or the soil.
  • When used properly, onsite systems protect public health and the environment by reducing disease transmission and removing pollution from surface and groundwater.
  • Individual onsite systems are typically regulated by states, tribes and local governments, while large capacity septic systems are regulated by the EPA.

Environmental Health professionals play an important role in managing onsite wastewater treatment systems. Septic system professionals are involved in installing, operating, maintaining, and repairing onsite systems. Professionals with local or state health departments evaluate potential sites for onsite systems, issue permits or licenses for technicians, conduct inspections, and enforce local regulations. Additionally, environmental health professionals partner with industries involved in developing land containing buildings using onsite systems to ensure that these treatment systems continue to discharge clean and usable water.  

In October 2019, the National Environmental Health Association (NEHA), and the National Onsite Wastewater Association (NOWRA), signed a Memorandum of Understanding (MOU) to formalize their mutual commitment to water quality protection. The MOU provides a framework for facilitating long-term mutual objectives, which include sustained contact among ground water professionals, sustained contact among leadership and staff of both organizations, and a cooperatively partnering on a variety of joint activities.

Available Resources & Programs

Preparedness & Response for Septic Systems

After a disaster, such as a hurricane, wildfire, or earthquake, septic systems may be damaged and fail to operate correctly. Ensuring that these systems function properly is essential to providing safe waste disposal for millions of Americans, yet there may be no standard safety protocol in place for using septic systems after a disaster occurs.

NEHA worked with subject matter experts and national partners to develop an easily accessible toolkit with guidance documents for different types of disasters.

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Wastewater Resources & Programs

diagram of septic system for drinking water

NEHA is also improving decentralized wastewater management by partnering with the US EPA in their septic activities to aid consumers and professionals in the field. NEHA is part of a select group of national organizations that signed a Memorandum of Understanding with US EPA to improve the quality and quantity of resources and education available to wastewater professionals, regulatory agencies, and other onsite wastewater stakeholders. Additionally, NEHA participates in EPA’s annual SepticSmart Week with outreach activities to encourage homeowners and communities to care for and maintain their septic systems.

The NEHA Flooding Preparedness and Response for Private Water Systems page includes a range of resources to assist private well and septic system users before, during, and after a hurricane or mass flooding disaster.

The US EPA How Your Septic System Can Impact Nearby Water Sources tool is a set of interactive diagrams which illustrate the relationship between septic systems and drinking water, septic systems and surface water, and ways to improve septic systems and better protect nearby water sources. These resources provide homeowner outreach and education to improve use and maintenance of residential septic systems. An example of the diagrams can be found to the left.




NOWRA logoNOWRA Online Septic Learning Academy

Taught by experts in the industry, NOWRA’s Academy offerings cover the fundamentals of the decentralized wastewater profession as well as advanced training in multiple topics. Septic system course offerings include those developed from a national perspective and those meeting specific state requirements.  

NOWRA Online Academy



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