The Regional Alternative Compliance System (RAC) is a revolutionary new funding system that provides a market-based, regional approach to stormwater treatment.
Contra Costa County is nestled in Northern California’s San Francisco Bay Area. This diverse county spans a mix of landscapes, from scenic hills and waterways to vibrant downtowns and historic industrial zones.
Most of Contra Costa’s watersheds flow directly into San Francisco Bay, making stormwater management essential.
But with limited funding, how do you protect water quality across such a varied landscape?
The answer lies in innovation. The Regional Alternative Compliance System, also called the RAC System, is a countywide solution for smarter stormwater treatment. Instead of building systems on every development site, the RAC System enables funding for larger, cost-effective regional projects strategically built in areas with targeted pollutants.
It’s a practical, equitable solution, helping treat runoff in the county’s environmental justice communities. The system has just completed a pilot project, Sutter Avenue Green Street. This road was transformed into a state-of-the-art green infrastructure corridor, capturing runoff from 23 acres, cleaning water, reducing flooding, and beautifying the block.
This system is managed by the Contra Costa Clean Water Program, allowing public agencies to channel limited funds to the places that need them most, helping every city meet stormwater permit compliance goals. With this proven model and strong regional collaboration, the system is poised to expand with more treatment projects.
This RAC System isn’t just smart, it’s scalable. It helps to shape a future where bold regional thinking comes together to drive lasting change.
Developed by the Cities of San Pablo and Walnut Creek, unincorporated Contra Costa County, and the Contra Costa Clean Water Program, the RAC is a first-of-its-kind model that provides sustainable long-term financing for larger, more strategic, regional green infrastructure projects.
Instead of requiring each individual infrastructure project to handle stormwater on-site, developers can purchase “compliance units” in larger, shared green infrastructure facilities. This improves efficiency, directs resources to pollution hotspots (often in disadvantaged communities), and creates a dedicated funding stream for long-term maintenance. It’s a scalable solution for stormwater managers across California and beyond.
Some development and redevelopment sites may have constraints (size, steep grades, etc.) that make it difficult to build on-site stormwater treatment. When a project has difficulty building MRP-required stormwater treatment on-site, it can use the Contra Costa County RAC System to comply with the MRP.
Municipalities may purchase compliance units to comply with MRP Provision C.3.j impervious surface retrofit requirements. Additionally, municipalities with Regulated Projects, such as large road reconstruction projects, could use the Contra Costa County RAC System to comply with the MRP. Municipalities may also act as “sellers” through the Contra Costa County RAC System.
Non-profits or other environmental organizations may be interested in building GSI facilities that can be partially funded by selling compliance units through the Contra Costa County RAC System.
Developers or contractors may be interested in building Off-Site GSI Projects to generate compliance units that can be sold through the Contra Costa County RAC System.
The RAC System is backed by $1.6M in U.S. EPA grants. RAC is being piloted now and will expand countywide by 2026, setting a model for stormwater managers across California.
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In September 2025, the Contra Costa County Regional Alternative Compliance (RAC) System was honored with the 2025 CASQA Award for Outstanding Stormwater Financial Strategy. View this press release for more details.
The Contra Costa County RAC System was developed through the United States Environmental Protection Agency (EPA), Region 9, Water Quality Improvement Fund Grants. The Contra Costa Clean Water Program (CCCWP) wishes to thank the following:
We couldn’t have done it without all of your help!
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