Background

The Contra Costa County Regional Alternative Compliance (RAC) System is a collaborative initiative partnership funded by the U.S. Environmental Protection Agency (EPA) through the San Francisco Bay Water Quality Improvement Fund. The RAC System was created to help local entities comply with the rigorous post-construction stormwater treatment requirements outlined in Provision C.3 of the San Francisco Bay Region Municipal Regional Stormwater Permit (MRP).

Why Was the RAC System Developed?

Many development and redevelopment projects face challenges in meeting stormwater treatment requirements due to site constraints, high costs, and concentrated legacy pollution in certain areas. Traditional approaches often require distributed green stormwater infrastructure (GSI), which can be expensive and difficult to maintain. The RAC System offers a flexible, cost-effective, and scientifically defensible alternative by allowing required stormwater treatment to be implemented off-site.

How Does the RAC System Work?

The RAC System enables the construction of regional GSI treatment facilities—called Off-Site GSI Projects—within Contra Costa County. These projects generate “compliance units,” which can be bought and sold through the RAC System. Developers, municipalities, and other parties that need stormwater compliance can purchase these units to meet their regulatory requirements. Sellers design and construct Off-Site GSI Projects, which must be certified by the RAC System before units can be sold. Buyers pay for compliance units and an annual fee to cover ongoing operations and maintenance (O&M) of the facilities.

Benefits of the RAC System

• Strategic Siting: Regional stormwater treatment facilities can be located in areas with greater legacy pollutant concerns, maximizing environmental benefit.
• Cost Savings: Larger facilities typically reduce capital and O&M costs per treated acre.
• Flexibility: The system supports projects with physical or site constraints that make on-site treatment difficult.
• Long-Term Performance: Designated O&M funding ensures facilities are properly maintained over time.

Who Can Participate?

• Developers: For projects where on-site stormwater treatment is impractical.
• Municipalities: To comply with impervious surface retrofit requirements or large road reconstruction projects.
• Non-profits & Environmental Organizations: Interested in building GSI facilities and funding them through compliance unit sales.
• Contractors: Those interested in constructing Off-Site GSI Projects

Oversight and Legal Basis

The RAC System was developed with input from local permittees, an advisory committee representing nine Bay Area counties, Caltrans, the Port of Oakland, the Water Quality Control Board, and EPA. It is legally enabled under MRP Provision C.3.e “alternative compliance” and is subject to ongoing reporting and verification requirements. The RAC System is managed by the RAC Joint Powers Authority (JPA).