Erosion Control - Construction Sites
Preventing Storm Water Pollution at Construction Sites
The most common pollutant from construction sites is erosion, where large amounts of sediment-laden water have the potential to flow into storm drains. The property owner is the legally responsible person (LRP) and must ensure that any water that leaves the construction site meets the minimum requirements for water quality. This means that pollution prevention best management practices (BMPs) such as wattles, silt fencing and gravel bags are strategically placed to prevent sediment and other pollutants from entering the storm drains. While most of the rainfall in Sonoma County occurs between October 1st and April 30th, pollution prevention is a year-round activity. Maintaining these BMPs helps protect the health of our waterways and our community.
Here is an example of what a properly maintained construction site might look like:
All construction sites are required to submit their plans to the Building Department for approval before permits are issued and before any construction begins.
- Construction sites <1 acre of land disturbance are required to prepare a simple Erosion and Sediment Control Plan (ESCP), which can be prepared and signed by the property owner or their contractor. Complete the form provided below.
- Construction sites with 1 acre or more of land disturbance are required to prepare a Storm Water Pollution Prevention Plan (SWPPP), which must be prepared by a Qualified SWPPP Developer (QSD) and signed by the property owner.
- All projects must implement and maintain proper BMPs.
All construction sites are subject to inspection by the Town and the North Coast Regional Water Quality Control Board. All construction projects shall conform to the Town of Windsor, Phase I Municipal Storm Water NPDES permit (Town Permit) and the Town's stormwater ordinance 2016-303, and Town MS4 inspections.
The North Coast Regional Water Quality Control Board Construction General Permit Order 2009-0009-DWQ was administratively terminated in 2025. All projects that disturb an acre or more of soil must obtain coverage under the 2022 Construction General Permit, per Construction Stormwater General Permit Order 2022-0057-DWQ.
Documents & Resources
Erosion and Sediment Control Form for <1 Acre Disturbance: Complete this form and include a site drawing with BMP locations. If a plan set is included for the project design, incorporate the notes from this form into the plans.
Storm Water BMPs for Small Construction Sites
Storm Water BMPs for Larger Construction Sites
California State Water Board Construction Stormwater Program
Frequently Asked Questions regarding the State requirements for the 2022 Storm Water Construction General Permit
Watch this short video for an overview of the storm water Construction General Permit from the California State Water Resources Control Board.
SWPPP Review Checklist-Town of Windsor