Pretreatment

The Federal and State Pretreatment Program gives regulatory authority for EPA, states, and municipal governments to control the discharge of industrial wastewater into municipal Wastewater Treatment Plants (WWTPs) or Publicly Owned Treatment Works (POTWs).   The objectives of the Pretreatment Program are to prevent pass-through, interference, or other adverse impacts to the POTW, its workers or the environment; to promote the beneficial reuse of biosolids, and to assure that all categorical pretreatment standards are met.  There are over 600 Significant Industrial Users (SIUs) who discharge industrial wastewater to more than 100 POTWs throughout the State of North Carolina.   

Updated September 16, 2023

PQL Letter

The North Carolina Pretreatment Consortium (NC-PC) has expressed the need for consistent minimum sampling limits that could be met by all State labs and provide the most appropriate data. In cooperation with NC-PC the Division has collaborated to provide a Practical Quantitation Limit (PQL) guidance letter. The Division believes that meeting the PQLs outlined in this letter will be achievable by most if not all labs across the State. The PQL letter provides a sampling sensitivity floor for common pollutants. The Division recognizes that some unique situations will require deviation from the guidelines presented in this document, for such cases we require that the program reach out to the Division and discuss possible changes. 

PQL Guidance Document

Q/A (Silver) Letter

DWR’s Pretreatment Staff received a set of questions related to the “March 2022 Silver Letter,” which contained general PQL Guidance. The Q/A letter contains detailed responses provided by DWR staff. The Division recommends that all pretreatment professionals review this STMP/LTMP/HWA development information. 

PQL Q/A Silver Letter 

Comp Guide Update for PQLs

If you have any further questions that are not addressed in these documents, please contact the Pretreatment staff listed below. 

Sewer Use Ordinance (SUO) 

This Model SUO includes many revisions to address the 2011 revisions to NCAC 15A 02H .0900 - Local Pretreatment Programs.  

• Model Pretreatment SUO revised August 26, 2011
• NC SUO Checklist August 2011
• Summary of SUO Comments
• Example Attorney's Statement

State Pretreatment Regulations

 The Rules are final and effective as of July 1, 2019.

• Pretreatment Rules:  15A NCAC 02H .0900

Federal Regulations

• General Pretreatment regulations: 40 CFR 403 (July 2012)
• Categorical Pretreatment Regulations: 40 CFRs 400-471
• EPA Dental Effluent Guidelines
• October 14, 2005, Streamlining of the Federal Pretreatment Regulations 
• Dental Amalgam Rule Guidance - 40 CFR 441
• See the Other Downloads Webpage for more information

Pretreatment Staff in Municipal Permitting Unit