Storm Water

    Storm Drain stencilWhat is storm water pollution and how is it created?

    Where does the rain that falls on the street go? If you live in the city, runoff from your yard and driveway probably flows into the street where it drops into storm drains… but then where does it go?

    Many people think that water for the storm drain system is treated at a wastewater treatment plant and all of the pollutants are removed. In truth, urban runoff flows untreated through the storm drain system. Anything thrown, swept or poured into the street, gutter or storm drain flows directly into our creeks without treatment or filtering. The problem is this runoff from pesticides and fertilizers, paint from brushes and containers rinsed in the gutter and toxic household chemicals.

    Storm water pollution is this urban runoff that has picked up pollutants as it flows through this urban runoff that has picked up pollutants as it flows through the storm drain system – a network of channels, gutters, and pipes that collect runoff from city streets, neighborhoods, farms construction sites and parking lots and empties into our local waterways.

    What you can do to prevent urban stormwater runoff:

    • Keep litter, pet wastes, leaves and debris out of street gutters and storm drains—these outlets drain directly to lake, streams, rivers and wetlands.

    • Apply lawn and garden chemicals sparingly and according to directions.

    • Dispose of used oil, antifreeze, paints and other household chemicals properly—not in storm sewers or drains. If your community does not already have a program for collecting household hazardous wastes, ask your local Storm Draingovernment to establish one.

    • Clean up spilled brake fluid, oil, grease and antifreeze. Do not hose them into the street where they can eventually reach local streams and lakes.

    • Control soil erosion on your property by planting ground cover and stabilizing erosion-prone areas.

    • Encourage local government officials to develop construction erosion and sediment control ordinances in your community.

    • Have your septic system inspected and pumped, at a minimum every three to five years, so that it operates properly.

    • Purchase household detergents and cleaners that are low in phosphorous to reduce the amount of nutrients discharged into our lakes, streams and coastal waters.

    (Source: EPA)

    Water Agency General Information

    The Sonoma County Flood Control and Water Conservation Act of 1949 established the Water Agency as a Flood Control and Water Conservation District.  The Water Agency was originally authorized to provide water supply and flood control services (See West’s Water Code Appendix Chapter 53, hereafter “The Agency Act”). 

    In 1958, the Water Agency formed eight geographic flood control zones, each encompassing a major watershed.  The core permit area encompasses the boundary of Zone 1A, which incorporates the Mark West Creek Watershed. The cities of Santa Rosa, Rohnert Park, Cotati and Sebastopol and the Town of Windsor all lay within Zone 1A.  The urban boundary area surrounding the City of Healdsburg lies within the boundaries of Zones 4A and 6A.  The urban boundary of Graton and a portion of the urban boundary of Sebastopol are located in Zone 5A.  Flood control facilities within Zone 1A were constructed as the Central Sonoma Watershed Project by the Water Agency in cooperation with the U.S. Department of Agriculture, Soil Conservation Service with the purpose of protecting the Santa Rosa urban area from flooding.  The construction of floodwater retarding structures and the straightening, shaping and stabilization of waterways began in 1958 and continued over the ensuing 25 years. 

    The Water Agency is a Permittee, since it owns portions of the municipal separate storm sewer system (MS4) in the permit boundary.  The Water Agency’s storm water management plan incorporates appropriate activities and best management practices (BMPs) for activities related to its flood control and general fund activities. 

    Water Agency Resources


    For more information

    For more information about the Water Agency's Stormwater program, please contact Kevin Booker via email at or via phone at (707) 521-1865.