Facility Regulatory Tour
Quick Reference

General Description

Publicly owned treatment works (POTWs) collect wastewater from homes, commercial buildings, and industrial facilities and transport it via a series of pipes, known as a collection system, to the treatment plant. Here, the POTW removes harmful organisms and other contaminants from the sewage so it can be discharged safely into the receiving stream.

Summary of Federal Requirements

POTWs must provide adequate notice to the Director of the following:

  • any new introduction of pollutants into the POTW from an indirect discharge that would be subject to section 301 or 306 of the CWA if the discharger were directly discharging those pollutants
  • any substantial change in the volume or character of pollutants being introduced into that POTW by a source introducing pollutants into the POTW at the time of issuance of the permit.

POTWs are required to have sufficient resources and qualified personnel to carry out the POTW pretreatment program.

POTWs must develop and implement an enforcement response plan that contains detailed procedures indicating how a POTW will investigate and respond to instances of industrial user noncompliance. At a minimum the plan must include:

  • describes how the POTW will investigate instances of noncompliance
  • describes the types of escalating enforcement responses the POTW will take in response to all anticipated types of industrial user violations and the time periods within which responses will take place
  • identifies (by title) the official(s) responsible for each type of response
  • adequately reflects the POTW's primary responsibility to enforce all applicable pretreatment requirements and standards.

POTWs maintain a list of significant industrial users and the criteria applicable to each industrial user.

Any POTW (or combination of POTWs operated by the same authority) with a total design flow greater than 5 million gal per day (mgd) and receiving from industrial users pollutants which pass through or interfere with the operation of the POTW, or are otherwise subject to pretreatment standards has a POTW pretreatment program.

(NOTE: The pretreatment program is not required if the NPDES state exercises its option to assume local responsibilities. The USEPA or authorized regulatory agency may require that a POTW with a design flow of 5 mgd or less develop a POTW pretreatment program if the nature or volume of the industrial influent, treatment process upsets, violations of POTW effluent limitations, contamination of municipal sludge, or other circumstances warrant, in order to prevent interference with the POTW or pass through.)

POTWs with approved Pretreatment Programs must provide the Approval Authority with a report that briefly describes the POTW's program activities, including activities of all participating agencies, if more than one jurisdiction is involved in the local program. The required report must be submitted no later than 1 yr after approval of the POTW's Pretreatment Program, and at least annually thereafter.

POTWs must keep records of all information resulting from monitoring activities. and records for all samples will include the following information:

  • the date, exact place, methods, and time of sampling and the names of the person or persons taking the samples
  • the dates analyses were performed
  • who performed analyses
  • the analytical techniques, methods used
  • the results of the analyses.

The following POTWs must provide the results of valid whole effluent biological toxicity testing to the Director:

  • all POTWs with design influent flows equal to or greater than one million gallons per day
  • all POTWs with approved pretreatment programs or POTWs required to develop a pretreatment program.

In addition to requirements promulgated under the Clean Water Act, there have also been requirements for POTWs promulgated under the Clean Air Act. NESHAPS standards have been established for both industrial and nonindustrial POTWs.

Summary of State Requirements

States typically regulate the training and experience needed to be a certified POTW operator.

Additionally, the state may be the NPDES permitting authority. The permit parameters will depend on the types of water being discharged into, the treatment type and capacity available at the POTW, and what pollutants are being discharged to the POTW.

Types of wastewater treatment that are primarily regulated at the state and local level include septic tanks, cess pools, leach fields, compost toilets and other individual sewage systems.

Laws and Statutes

Clean Air Act
Clean Water Act

Back to Top  Page Top
Regulatory Sources
40 CFR 122.21
EPA Administered Permit Programs: The National Pollutant Discharge Elimination System, Subpart B: Subpart B: Permit Application and Special NPDES Program Requirements

40 CFR 403
General Pretreatment Regulations for Existing and New Sources of Pollution
Related Topics
No items available.
Last Updated: July 28, 2017