All facilities in the United States that discharge wastewater to surface waters (e.g. rivers, lakes or coastal waters} must obtain a permit under the National Pollutant Discharge Elimination System, a Clean Water Act program administered by EPA and state agencies. The facilities covered include sewage treatment plants, industrial and commercial plants, military bases and other facilities. Most permittees are required to regularly collect wastewater samples and analyze them for compliance with permit requirements, and report the results either to EPA or the state agency.
