Pretreatment Program

The Colorado River Basin Region (Regional Water Board) developed this web page to provide information on the Federal, State and Regional Water Board Pretreatment Program.

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. Generally, POTWs are designed to treat domestic sewage only. However, POTWs also receive wastewater from industrial (non-domestic) and commercial users. The practice of removing pollutants from industrial and commercial wastewaters before they are discharged into municipal sewage treatment systems is known as “pretreatment.” For example, when a restaurant installs a grease trap in its plumbing system to remove Fats, Oils and Grease (FOG), that’s pretreatment.

Quick Links

Overview | Federal, State, and Regional Board Web Links on Pretreatment and FOG | Pretreatment Conference Power Point Presentation Web Links | Resources for Pretreatment Program Submittals | Questions or Comments?


In 1978, U.S. EPA promulgated extensive regulations requiring many POTWs to develop and implement local pretreatment programs. The General Pretreatment Regulations at 40 CFR 403.1 et seq. establish the responsibilities of government agencies, industries, non-domestic users and the public to implement pretreatment standards to control industrial pollutants that may pass through or interfere with publicly owned treatment works (POTWs) or contaminate sewage sludge

U.S. EPA delegated the responsibility to oversee these pretreatment programs to the State Water Board and Regional Water Boards in 1989. As a result, the State and Regional Water Boards are responsible for the review and approval of new and modified POTW pretreatment programs. The NPDES permits for these POTWs spell out the pretreatment program monitoring and reporting requirements.

The Regional Water Board’s pretreatment program includes pretreatment compliance audits and inspections, annual and semiannual report reviews, program modifications, and enforcement activities.

Pretreatment compliance inspections verify the compliance status of POTWs, focusing on the POTW’s own compliance monitoring and enforcement activities. Pretreatment compliance audits involve a comprehensive review of all elements of a POTW’s pretreatment program. Audits take place every five years. Inspections usually occur every year, except when an audit is scheduled.

Federal, State, and Regional Board Web Links on Pretreatment and FOG

Pretreatment Conference Power Point Presentations Web Links

The following web links are from the Pretreatment Power Point presentations:

Resources for Pretreatment Program Submittals

USEPA-State and Regional Water Board Strategy on Pretreatment and Sanitary Sewer Overflows:
USEPA Region 9 is working with the State and Regional Water Board to develop and implement procedures to adopt pretreatment programs and conduct pretreatment compliance inspections and audits.

POTWs are required to have pretreatment programs if they receive industrial pollutants that could pass through or interfere with POTW operations.

If a Pretreatment Program is required, Pretreatment Program Development and Approval Standards Requirements for submittal of a Pretreatment Program will be submitted to the Regional Water Board for approval.

This sample Pretreatment Compliance Audit checklist and its accompanying instructions identify information that might be reviewed by Approval Authorities (EPA and States) in order to assess a POTW’s implementation of its approved Pretreatment Program with respect to approved program procedures, as well as state and federal policies and regulations.

Final Pretreatment Streamlining Rule:
Copy of Pretreatment Regulations incorporating changes made by the final Pretreatment Streamlining Rule (64 pp, 398k)

Sewer Ordinance:

This document provides guidance on municipal ordinances to implement and enforce a pretreatment program consistent with the Clean Water Act requirements.

Industrial Waste Survey:
The Industrial Waste Survey (IWS) is a required part of the pretreatment program. The IWS is conducted primarily to identify the nature and quantity of pollutants entering the Publicly Owned Treatment Works (POTW) system from industrial sources, and to identify the industries responsible for discharging the pollutants. This information is critical for pretreatment program administration since it provides a basis for many activities, such as determining sampling and monitoring needs (both at industries and in the POTW system), developing local limits for industrial users (IUs), estimating manpower and equipment needs, and identifying sources of known or potential POTW problems.

The four general activities the POTW must address in conducting an acceptable IWS are:

  • Compiling a comprehensive list of potential IUs located in the POTW service area
  • Surveying each of these IUs to collect necessary information
  • Conducting follow-up activities, where needed, to obtain the necessary information
  • Analyzing and presenting the data obtained in support of its pretreatment program.

Below are IWS instructions, survey form, and information that will need to be reported to the Regional Board (Forms 1, 2, & 3)

  • Industrial Waste Survey Instructions and Forms - [ PDF ]

Local Limits:
Local limits are developed to reflect specific needs and capabilities at individual POTWs and designed to protect the POTW receiving waters. Regulations at 40 CFR 403.8(f)(4) state that POTW Pretreatment Programs must develop local limits or demonstrate that they are unnecessary; 40 CFR 403.5(c) states that local limits are needed when pollutants are received that could result in pass through or interference at the POTW. Essentially, local limits translate the general prohibited discharge standards of 40 CFR 403.5 to site-specific needs at the end of pipe.

This is the final technically-based local limits guidance manual for municipalities that operate pretreatment programs. This manual provides guidance to municipalities on the development and implementation of local controls for discharges of industrial or commercial wastes to sewage treatment facilities. This manual provides technical assistance and guidance on:

Categorical Limits:
Categorical Pretreatment Standards are limitations on pollutant discharges to publicly owned treatment works (POTWs) at the end of process unit, promulgated by EPA in accordance with Section 307 of the Clean Water Act that apply to specific process wastewaters of particular industrial categories. These are national, technology-based standards that apply regardless of whether or not the POTW has an approved pretreatment program or the industrial user has been issued a permit. Such industries are called Categorical Industrial Users. The standards applicable to industrial discharges to a POTW collection system are designated in the Effluent Guidelines & Limitations [Parts 405-471] by the terms “Pretreatment Standards for Existing Sources” (or “PSES”) and “Pretreatment Standards for New Sources” (or “PSNS”).

Enforcement Response Plan:
Guidance for Developing Control Authority Enforcement Response Plans - This manual provides guidance to Control Authority personnel in developing an enforcement response plan to remedy violations of a local pretreatment program.

Funding Program:
Federal regulations 40 CFR 403.10(f)(3) require that adequate funds be available to support a Pretreatment Program.  This includes personnel costs, operation and maintenance costs, sampling and training costs and other costs associated with implementing the requirements under 40 CFR 403.10(f)(1) through (2).  Some agencies fund its program though pretreatment surcharges for discharges into the sewer system.

General and Individual Permits:
A general permit is an NPDES permit that covers several facilities that have the same type of discharge and are located in a specific geographic area. A general permit applies the same or similar conditions to all dischargers covered under the general permit. Using a general permit to cover numerous facilities reduces paperwork for permitting authorities and permittees, and ensures consistency of permit conditions for similar facilities.

An individual permit is a permit specifically tailored to an individual facility. Once a facility submits the appropriate application(s), the permitting authority develops a permit for that particular facility based on the information contained in the permit application (e.g., type of activity, nature of discharge).

Other Industrial Pretreatment and Grease Management Resources:

Regional Water Board Approval Process:
The Regional Water Board will include standard pretreatment implementation requirements for municipal permits in NPDES discharge permits as an approved pretreatment program is approved by the Regional Water Board.

Pretreatment Program Example

Questions or Comments about the Pretreatment Program?