Storm Water Quality and Management

windsor_digital_ads_300X250 squareThe Town of Windsor maintains a Municipal Separate Storm Sewer System (MS4) that directs storm water from our streets, homes, and businesses to pipes beneath the streets that flow directly into nearby streams. Under the Federal Pollution Control Act (Clean Water Act) section 402(p), an MS4 National Pollutant Discharge Elimination System (NPDES) Permit is required for cities to discharge storm water to urban water ways. 

The storm sewer system is separate from the sanitary sewer system, which means:

  • All storm drains in the street and parking lots ARE NOT channeled to the Town’s wastewater treatment plant. 
  • Every substance that is spilled, accumulated, or accidentally dumped on the street or parking lot will eventually be carried by wind, rain or irrigation runoff into Windsor’s creeks and out to the Russian River. 

Contaminants from urban runoff are known to negatively impact water quality and urban wildlife habitat. Under the MS4 NPDES Permit (the Permit), cities are responsible for ensuring that certain practices are followed to reduce the concentration of contaminants to storm water, such as heavy metals, phosphorus, nitrates, bacteria and others. The greater amount of concrete and pavement in a city, the higher the concentration of pollutants to the storm drain system, creeks, and the Russian River.

20220315_102909In Windsor, the North Coast Regional Water Quality Control Board of the State of California (Regional Board) implements and enforces the MS4 NPDES Program, and typically updates the Permit for our region every five years. Windsor is a Co-Permittee with the County of Sonoma, City of Cloverdale, City of Cotati, City of Healdsburg, City of Rohnert Park, City of Santa Rosa, City of Sebastopol, Sonoma Water, and City of Ukiah under permit No. CA0025054, Order No. R1-2015-0030. 

The Town’s MS4 pollution prevention program is a result of the comprehensive requirements of the Permit. You may see our staff inspecting your business for potential pollutants, weeding or planting in streetside swales, ensuring compliance with regional standards for storm water treatment systems, or collecting water samples from Windsor’s creeks. The Permit includes:

  • Public outreach and education
  • Industrial & commercial facility inspection and education to help keep contaminants from entering the MS4 
  • Post-construction storm water capture and treatment, known as Low Impact Development (LID)
  • Construction site inspection for erosion prevention and pollution control 
  • Training Town employees on pollution prevention
  • Response to and prevention of illegal discharges and illegal connections to the MS4
  • Sampling to monitor water quality in streams and storm water runoff 

The Town staff works hard to implement the Permit, but we need your help! You and your family or business can help improve water quality in Windsor’s creeks by making simple changes to your daily routine. To learn how, visit the Town's Pollution Prevention page or the Town's partners at 

To view the entire Permit and its jurisdictional boundary maps, click here: 4-16-09 ( To view the regional water quality monitoring requirements, click here: Revised MRP R1-2015-0030 ( 

Report Spills
Please report any clogged storm drain inlets, spills or dumping that could enter the storm drain system, and faded or missing storm drain labels:

  • Engineering Division, Public Works, (707) 838-1006 or email (Monday to Thursday, 7 a.m. to 6 p.m.) 
  • After hours, please call (707) 838-1000


Storm Water-Related Resources

Stormwater Quality Ordinance 2016-303

Stormwater Quality Ordinance 2008-249
Erosion Control Ordinance 2008-246
Reducing Pollutants in Storm Water Ordinance 2010-261
Resolution 3142-14 Adopting C.O.S.R. LID (Low Impact Development) Manual
City of Santa Rosa LID (Low Impact Development) Technical Design Manual and related documents

The Russian River Watershed Association offers extensive links to information on gardening, landscaping, fire defense, water conservation, and other topics related to caring for our watershed. Visit the RRWA Resource Library. 

Contact Us
Town of Windsor Storm Water Program Coordinator 
(707) 838-5385