Onsite wastewater treatment systems refer to any system used to treat and dispose of/recycle wastewater from homes, businesses, industrial facilities, and sometimes entire communities. Environmental health professionals working at local or state health departments evaluate potential sites for onsite systems, issue permits or licenses for technicians, conduct inspections, and enforce local regulations.

  • 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 10% to over 50% 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.

Learn More

  • Interactive Diagrams on How Your Septic System Can Impact Nearby Water Sources, EPA | Webpage
  • Septic Systems after a disaster, NEHA | Webpage
  • Flooding Preparedness and Response for Private Water Systems, NEHA | Webpage
  • EPA Septic System Technical Resources, EPA | Webpage
  • Memorandum of Understanding (MOU) with the National Onsite Wastewater Association (NOWRA), NEHA | PDF
  • NOWRA Online Septic Learning Academy: Courses include the fundamentals of the decentralized wastewater profession, advanced training by topic, and national and state septic system courses | Webpage