National Pollutant Discharge Elimination System (NPDES), is a discharging system that is covered under the Ohio EPA statewide general permit in situations where on-site dispersal of wastewater is not an option.  NPDES systems include new aeration systems with ultraviolet lighting or some other additional treatment that reduces the bacteria to safe discharge standards. The homeowner is required to have these systems sampled yearly to assure they continue to meet EPA discharge standards. These systems require two permits, one from the local health department and one from the Ohio EPA.

Properties with an NPDES are required to have a service contract with a registered service provider.