California Water Boards' Annual Performance Report - Fiscal Year 2020-21 

TECHNICAL CONSIDERATIONS

  • Data Source: CIWQS. Period July 1,  2020 to June 30,  2021 .
  • Unit of Measure: Number of active NPDES permits for Major facilities as of June 30,  2021 .
  • Data Definitions: Permits issued during  20-21 : adoption date between July 1,  2020 to June 30,  2021 . Permits Current: Permits not expired and not issued in FY  20-21 . Permits Expired: permits with an expiration date before June 30,  2020 .
  • References:

GLOSSARY

Major Facility
Major municipal dischargers include all facilities with design flows of greater than one million gallons per day and facilities with approved industrial pretreatment programs. Major industrial facilities are determined based on specific ratings criteria developed by US EPA/State.

National Pollutant Discharge Elimination System (NPDES)
The NPDES permit program (Section 402 of the Clean Water Act) 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. Individual homes that are connected to a municipal system, use a septic system, or do not have a surface discharge do not need an NPDES permit; however, industrial, municipal, and other facilities must obtain permits if their discharges go directly to surface waters. US EPA has approved the Water Board's program to issue NPDES permits.

NPDES Permit
The Clean Water Act prohibits anybody from discharging "pollutants" through a "point source" into a "water of the United States" unless they have an NPDES permit. The permit contains limits on what can be discharged, monitoring and reporting requirements, and other provisions to protect water quality and public health. In essence, the permit translates general requirements of the Clean Water Act into specific provisions tailored to the operations of each person discharging pollutants.