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The Stormwater utility is responsible for the operation and maintenance of 620 miles of pipe, 72 pump stations, and over 100 discharge outfall pipes that collect and route runoff from the streets and gutters, and discharges it to our local rivers, creeks, and sloughs.  The Stormwater utility also manages the City’s National Pollutant Discharge Elimination Permit (NPDES) and all the monitoring, testing, education and programs required under the permit. 


The NPDES Stormwater Program regulates stormwater discharges from three potential sources:

  • Construction activities
  • Industrial activities
  • Municipal stormwater system


Municipal Stormwater System

Stormwater runoff is generated when precipitation from rain and snow melt flows over land and does not absorb into the ground.  As the runoff flows over the land or impervious surfaces (paved streets, parking lots, and building rooftops), it accumulates debris, chemicals, sediment, and other pollutants that could adversely affect water quality.  Stockton’s stormwater is collected in catch basins and is transported, untreated, directly into our local rivers, creeks, and sloughs, and eventually the Delta.  The primary method to control stormwater contaminants is the use of best management practices (BMPs), that stops contaminants from entering the system.


Municipal Separate Storm Sewer System (MS4) permits are required under the Clean Water Act and require the discharger to develop and implement a Storm Water Management Plan with the goal of reducing the discharge of pollutants to the Maximum Extent Practicable (MEP).  The management plans specify what best management practices (BMPs) will be used to address certain program areas, such as public education and outreach; illicit discharge detection and elimination; construction and post-construction; and good housekeeping for municipal operations.  Each year the City is required to provide an Annual Report to the State on their Stormwater Program and BMPs.


Construction Activities

Operators of construction sites that are one-acre or larger, including smaller sites that are part of a larger common plan of development are monitored under the State’s Construction General Permit.  The Stormwater Program also requires specific control measures for post-construction runoff from new developments and redeveloped areas. 


The Stormwater Quality Control Criteria Plan (SWQCCP) provides development standards on these controls, including general site control measures, site-specific source control measures, and treatment control measures for the following:

  • Home subdivisions with 10 or more housing units
  • Commercial developments with impervious areas greater than 5,000 sq. ft.
  • Automotive repair shops with impervious areas greater than 5,000 sq. ft.
  • Restaurants
  • Parking lots greater than 5,000 sq. ft. or with 25 or more parking spaces
  • Streets and roads with one acre or more of impervious area
  • Retail gas outlets with 5,000 or more sq. ft. of impervious area


Industrial Activities

The Stormwater Program works with local industries to prevent stormwater pollution with the following actions:

 Industrial companies may require authorization under an NPDES industrial stormwater permit for stormwater discharges.


Related Documents 

Other related documents available:

External Links

Appendices for the NPDES Municipal Stormwater Program ROWD & Proposed SWMP  

Municipal Separate Storm Sewer Systems (MS4s) 

U.S. Environmental Protection Agency - Stormwater Discharge from Construction Activities 

U.S. Environmental Protection Agency - Stormwater Discharge from Industrial Activities 

California Environmental Protection Agency - Stormwater Municipal Program PHASE 1

State Water Resources Control Board - Stormwater Permits

Stormwater Pollution Prevention Plans

Stockton Municipal Code, Section 13.16 Stormwater Management Discharge Control

Stockton Municipal Code, Section 13.20 Stormwater Quality Control Criteria Plan

This City of Stockton web page last reviewed on --- 11/14/2013