Welcome to the State Water Resources Control Board Welcome to the California Environmental Protection Agency
Governor's Website Visit the Water Board Members Page
My Water Quality
Performance Report

National Pollutant Discharge Elimination System (NPDES) - Wastewater

As authorized by the Clean Water Act (CWA), the National Pollutant Discharge Elimination System (NPDES) Permit Program controls water pollution by regulating point sources that discharge pollutants into waters of the United States. Point sources are discrete conveyances such as pipes or man-made ditches. Since its introduction in 1972, the NPDES Program has been responsible for significant improvements to our Nation's and State’s water quality.

Quick Links

What's New!

The Role of the State and Regional Water Quality Control Boards

It is the responsibility of the Water Boards to preserve and enhance the quality of the State's waters through the development of water quality control plans and the issuance of waste discharge requirements (WDRs). WDRs for discharges to surface waters also serve as NPDES permits.

The State Water Board establishes policies and regulations that help protect and restore the water quality in California. The State Water Board also coordinates with and supports Regional Water Board efforts, and reviews Regional Water Board actions. The Regional Water Boards monitor and enforce State and federal plans, policies, and regulations. Each Regional Water Board makes critical water quality decisions for its region. Regional Boundaries are on watersheds. In addition to issuing WDRs, these decisions include setting standards, determining compliance with WDRs, and taking appropriate enforcement actions.

While the State Water Board has issued a few NPDES permits, the vast majority of NPDES permits are issued by the Regional Water Boards. Typically, NPDES permits are issued for a five-year term. Occasionally, a permit would be issued with a term less than five years, such the Aquatic Pesticides Emergency Permit Order No. 2001-12-DWQ.

Individual Permits

An individual permit is tailored for a specific discharge. The State or Regional Water Board issues a permit for that particular discharge based on information (type of activity, nature of discharge, receiving water quality, etc.) contained in the application.

General Permits

A general permit is developed and issued by a State or Regional Water Quality Control Boards to cover multiple facilities within a specific category. General permits may offer a cost-effective option for the State or Regional Water Board because of the large number of facilities that can be covered under a single permit. According to 40 CFR §122.28, general permits may be written to cover categories of point sources having common elements, such as:

  • Storm water point sources ("Storm Water" is a separate program at the State Water Board)
  • Facilities that involve the same or substantially similar types of operations
  • Facilities that discharge the same types of wastewater
  • Facilities that require the same effluent limitations or operating conditions
  • Facilities that require the same monitoring where tiered conditions may be used for minor differences within class (e.g., size or seasonal activity)
  • Facilities that are more appropriately regulated by a general permit

General permits, however, may only be issued to dischargers within a specific geographical area such as the following:

  • Designated planning area
  • Sewer district
  • City, County, or State boundary
  • State highway system
  • Standard metropolitan statistical area
  • Urbanized area

The use of general permits allows the Water Boards to allocate resources in a more efficient manner and to provide more timely permit coverage. For example, a large number of facilities that have certain elements in common may be covered under a general permit without expending the time and money necessary to issue an individual permit to each of these facilities. In addition, the use of a general permit ensures consistency of permit conditions for similar facilities.

List of General Permits (Excel)

The link above provides a list of NPDES Wastewater General Permits throughout California. If you have a question on a specific general permit, please contact the appropriate Regional Water Board or the State Water Board.

Permitting Process

The process begins when a discharger submits an application to the appropriate Regional Water Board. Among other things, the application must describe the wastes to be discharged, the setting for the discharge, and the method of treatment or containment. Once the application is deemed complete, the State or Regional Water Board staff will draft a permit, which must be adopted by the State or Regional Water Board before any discharge can occur.

The specific steps to obtain an NPDES permit are as follows:

  1. File the appropriate NPDES application forms with the Regional Water Board.
  2. State or Regional Water Board staff reviews the application for completeness and may request additional information.
  3. Staff determines if the discharge is to be permitted or prohibited. If a permit is needed and the application is complete, staff prepares a draft and sends out a notice for a 30-day public comment period.
  4. The discharger must publish the public notice for one day in the largest circulated paper in the municipality or county and submit proof of posting or publication to the Regional Water Board within 15 days after posting or publication.
  5. The Regional Water Board holds a public hearing after the 30-day public notification. The State or Regional Water Board may adopt the permit as proposed or with modification, or not adopt it at all. A majority vote of the Water Board members is required to adopt the permit. USEPA has 30 days to object to the draft permit, and the objection must be satisfied before the permit becomes effective.

The permit issuance process takes approximately six months, but may take longer depending upon the nature of the discharge.

Applying for a New Individual NPDES Permit

Dischargers to surface waters will need one or more of the following federal NPDES permit application forms:

  • Form 1 General information completed in conjunction with Forms 2B, 2C, 2D, 2E, 2F, Standard Form 2A
  • Form 2A Publicly-Owned Treatment Works
  • Form 2B Concentrated animal feeding operations and aquatic animal production facilities. New applications or renewals
  • Form 2C Existing manufacturing, commercial, mining, and silvicultural operations (including federal facilities)
  • Form 2D New manufacturing, mining, commercial and silvicultural operations.
  • Form 2E New applications or renewals of non-manufacturing facilities, trailer parks, service stations, laundromats, commercial facilities, etc.
  • Form 2F Storm water discharges associated with industrial activity.

Renewing an NPDES Permit

As stated above, NPDES permits typically expire five years after issuance and must be reissued every five years or less. During the reissuance process the discharger must comply with all conditions of the existing permit until a new final permit is reissued.

Permit Modifications

In a permit modification, only the conditions subject to change are reconsidered while all other permit conditions remain in effect. However, the entire permit may be reconsidered when it is revoked and reissued. A permit modification may be triggered in several ways. For example, a staff person at one of the Water Boards conducting an inspection of a facility that finds a need for the modification (i.e., the improper classification of an industry, new treatment process, new waste stream), or information submitted by the discharger may suggest the need for a change.

There are two classifications of modifications: major and minor. From a procedural standpoint, they differ primarily with respect to the public notice requirement. Major modifications require public notice; minor modifications do not.

Virtually all modifications that result in less stringent conditions must be treated as major modifications, with provisions for public notice and comment. Conditions that would necessitate a major modification of a permit are described in 40 CFR §122.62.

Causes for modification, but not revocation and reissuance:

  • Material and substantial alterations or additions to the permitted facility or activity occurred after permit issuance which justify new permit;
  • New information not available at the time of permit issuance (other than revised regulations, guidance, or test methods) justifies new permit conditions;
  • Standards or regulations on which the permit was based have been changed by promulgation of amended standards or regulations or by judicial decision;
  • Good cause exists for modification of a compliance schedule, such as an act of God, strike, flood, or materials shortage or other events over which the discharger has little or no control and for which there is no reasonably available remedy;
  • Discharger has filed a request for a variance under CWA section 301(c), 301(g), 301(h), 301(i), 301(k), or 316(a) or for “fundamentally different factors” within the time specified in 40 CFR 122.21;
  • When required by the "reopener" conditions in a permit;
  • At the request of the discharger who qualifies for effluent limitations on a net basis or when a discharger in no longer eligible for net limitations;
  • Per 40 CFR 403.8(e), under the authority of CWA section 402(b)(1)(C), the Approval Authority may modify, or revoke and reissue a POTW's Permit in order to:
          (1) To comply with the requirements of Pretreatment regulations; and
          (2) Incorporate a permit modification approved under CWA section 301(h) or 301(i);
  • Failure of a State to notify another State whose waters may be affected by a discharge;
  • When the level of discharge of any pollutant which is not limited in the permit exceeds the level which can be achieved by the appropriate technology-based treatment requirements;
  • To establish a “notification level;”
  • To modify a schedule of compliance to reflect the time lost during construction;
  • To include an effluent limitation requiring implementation of a minimum control measure(s) for a small MS4;
  • To correct technical mistakes;
  • When the discharger has installed the treatment technology considered by the permit writer in setting effluent limitations, but has been unable to achieve those limitations; or
  • When required by a permit condition to incorporate a land application plan for beneficial reuse of sewage sludge, to revise an existing land application plan, or to add a land application plan.

Causes for modification or revocation and reissuance:

  • Cause exists for termination under 40 CFR 122.64 and the permitting authority determines that modification or revocation and reissuance is appropriate; or
  • For the transfer of a permit.

Minor modifications are generally non-substantive changes. The conditions for minor modification are described in 40 CFR §122.63 and may only:

  • Correct typographical errors;
  • Require more frequent monitoring or reporting by the discharger;
  • Change an interim compliance date in a compliance schedule, but not to more than 120 days after the date specified in the existing permit or to interfere with attainment of the final compliance date;
  • Allow for a change in ownership or operational control of a facility where the no other change in the permit is necessary;
  • Change the construction schedule for a discharger which is a new source;
  • Delete a point source outfall when discharge from that outfall is terminated and does not result in discharge of pollutants from other outfalls except in accordance with permit limits;
  • Incorporate conditions of a POTW pretreatment program that has been approved in accordance with 40 CFR 403.11 as enforceable conditions of the POTW permit.

Permit Rescission

A discharger no longer needing a permit should apply for rescission. In order to rescind an NPDES permit, the facility owner or authorized representative should submit a request to the State or appropriate Regional Water Board. The request should include the permit number, name and address of the facility, facility owner/operator, and reason for the rescission.


  • NPDES Permit Fees
    • Discharges of Pesticides
      • Vector Control - see Section 2200(b)(6)
      • Other Pesticides Permits - see Category 3 of Section 2200(b)(9)
    • Flow <100 MGD
    • Flow >100 MGD
    • Wet Weather Facilities
    • Aquaculture
    • Geothermal Facilities
    • De minimis Discharges
  • Fee Surcharges

Sign Up for SMR Email Reminders (for Facilities that are NOT submitting electronic SMRs)

The Water Boards are trying to increase awareness of potential mandatory minimum penalties (MMPs) due to late self-monitoring reports (SMR). You may participate in this program by completing the form below and submitting it to the CIWQS Help Center.

This program will send auto-generated email reminders. An email will be sent towards the beginning of the year listing reports due that year and 45 days prior to the due date of each report.

Facilities submitting SMRs via eSMR do not need to use this form. Email notifications will be sent to the Legally Responsible Officials and Data Submitters associated to the facility.

This program is voluntary. Failure to receive the reminder emails does not relieve Permittees of their requirements to submit SMRs.

Please contact the CIWQS Help Center with questions regarding this program.

More Information

Questions or Comments?