Pretreatment Program

Pretreatment is the reduction, the elimination, or the alteration of pollutants in wastewater to a less harmful state prior to discharging the wastewater to the sanitary sewer system. DC WASA's federally mandated Industrial Pretreatment Program was established in 1986, as required by the Clean Water Act, to regulate non-domestic (e.g., industrial) discharges that introduce pollutants to the sanitary sewer system.

DC WASA's Industrial Pretreatment Program has the following objectives:

  • Prevent the introduction of pollutants that will interfere with the operation of DC WASA's wastewater treatment plant
  • Prevent the pass-through of pollutants to protect the Potomac River water quality and maintain compliance with DC WASA's National Pollutant Discharge Elimination System permit
  • Improve opportunities to recycle and reclaim municipal and industrial wastewaters and sludges
  • Protect the health and safety of the general public and DC WASA workers

Our approved Industrial Pretreatment Program is under the direct supervision of the U.S. Environmental Protection Agency (EPA), Region III office. We issue wastewater permits under this program to regulate non-domestic wastewater discharged into the District of Columbia's sanitary and combined sewer system. The Program meets its objectives by establishing discharge standards for pollutants of concern and through permitting Significant Industrial Users (SIUs), testing SIU discharges for compliance with permit limits, and routinely conducting comprehensive facility inspections.

While neighboring jurisdictions discharge wastewater into DC WASA's collection system, industrial users from Prince Georges, Montgomery, Fairfax, and Loudoun counties must follow the rules and regulations of their jurisdictional pretreatment programs, in addition to meeting the discharge standards for DC WASA.

For more information, you can download a copy of DC WASA's Pretreatment Annual Report. (PDF 14.8 mb)