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Grading, Drainage, & Storm Water

Grading, Drainage, & Storm Water is a section within the Engineering and Construction division that reviews and issues permits related to grading, drainage and storm water for properties in unincorporated Sonoma County.

  • Published on July 30, 2019

    Permit Sonoma is part of a public/private partnership to reduce pollution in the Sonoma Creek and Petaluma River watersheds.

  • Published on October 5, 2018

    The Water Board mandates that contractors meet specific storm water construction practices to prevent harmful pollutants from entering our watershed. Sonoma County is required by our permit from the Water Board to enforce compliance with these requirements. The County has been working with contractors in Larkfield and Mark West areas since August to get voluntary compliance and to notify them of the requirements.

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Drainage is the collection, conveyance, containment, and/or discharge of storm water runoff. A drainage system includes constructed and/or natural features that work together to collect, convey, channel, hold, inhibit, retain, detain, infiltrate, divert, treat, or filter storm water runoff, including detention and retention basins, overland flow paths, pipes, channels, and the inlets and outlets to these features.


Grading is the removal or deposition of earth material by artificial means. Earth material is defined as any rock or natural soil or combination thereof. Grading is generally a combination of excavation (cuts) and placement (fill) of soil. Common examples of grading include, but are not limited to, construction of driveways, building pads, site improvements or reservoirs, and restoration/stabilization of hillsides, slopes or stream banks. Grading does not include routine farming practices.

A grading permit is required prior to commencing any grading or related work, including preparatory site clearing and soil disturbance, except where exempted from permit requirements by Sonoma County Code section 11.04.010.A.

Grading and Drainage Ordinance (Sonoma County Code Chapter 11)

Storm Water

Storm water is any storm water runoff, snow melt, or surface runoff. Generally, storm water runoff occurs when rainfall flows over the ground.

Storm Water Quality Ordinance (Sonoma County Code Chapter 11A)

Contact Information

Contact us by Phone
Monday – Tuesday
Thursday – Friday
8:00 AM – 4:00 PM
10:30 AM – 4:00 PM
Permit Sonoma
2550 Ventura Avenue
Santa Rosa, CA 95403
38.465074, -122.723705


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