Pretreatment Program

The Pretreatment Program administers local, state and federal regulations affecting area businesses and the quality of the wastewater discharged into the City of Winston-Salem’s wastewater treatment system. These regulations were implemented:

  • To prevent the introduction of pollutants into the municipal wastewater system which will interfere with the operation of the system or contaminate the resulting sludge;
  • To prevent the introduction of pollutants into the municipal wastewater system which will pass through the wastewater system, inadequately treated, into any waters of the state or otherwise be incompatible with the system;
  • To promote reuse and recycling of wastewater and sludge from the municipal system;
  • To protect both municipal personnel who may be affected by sewage, sludge, and effluent in the course of their employment as well as protecting the general public;
  • To provide for equitable distribution of the cost of construction, operation, maintenance and improvement of the municipal wastewater system; and
  • To ensure that the municipality complies with its National Pollutant Discharge Elimination System (NPDES) permit conditions, sludge use and disposal requirements and any other federal or state laws to which the municipal wastewater system is subject.

Area businesses are required to install, operate and adequately maintain pretreatment equipment and/or systems to remove those pollutants that could otherwise damage or obstruct the wastewater collection system; or interfere with or pass through the wastewater treatment process. Examples of such pollutants include heavy metals, cyanide, toxic organics, and acidic or caustic wastes from industrial operations. The wastewater from restaurants and other food service industries are often more problematic due to conventional pollutants such as grease and solids.

Some major elements of the city’s Pretreatment Program include the review of pretreatment designs, the issuance of permits, the performance of inspections, the collection of samples, the review of permittee self-monitoring reports and the initiation of enforcement activities when appropriate.


The Pretreatment Program staff conducts inspections, surveillance and monitoring of industrial wastewater sources discharging to the City’s wastewater collection system and treatment plants. The monitoring and inspections are performed in order to independently verify compliance with all applicable pretreatment standards. Inspections of Significant Industrial Users are conducted at least annually.

Unannounced monitoring of SIU’s are usually conducted quarterly. Other monitoring and inspection activities are conducted on an as needed basis. Often these activities are related to problems or unusual conditions noted either at one of the wastewater treatment plants or within the wastewater collection system. They may also be a part of an investigation initiated subsequent to an anonymous report of suspicious activity or illegal dumping. If you have any question about a suspicious discharge to the sanitary sewer system, please contact a Pretreatment Program staff member at 336-765-0130. Your assistance would be appreciated and your confidentiality respected.


The City of Winston-Salem Pretreatment Program inspects and monitors industrial and commercial wastewater sources discharging to the City’s wastewater collection system to verify compliance with all applicable pretreatment standards.

Any facility whose wastewater service line is not already connected at a wastewater manhole would be required to have a control manhole if:

  • The facility is or will be discharging wastewater regulated under the Sewer Use Resolution; or
  • The city can show through documented historical data or information that problems such as line stoppages, backups, overflows, corrosion, high grease or solids, etc. exist at the part of the collection system to be used by the facility.

Control manholes shall be located on the facilities premises and be constructed in the right of way without obstruction by landscaping or parked vehicles. See the Water & Sewer Technical Specifications under the Forms & Application Section.

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