Urban Stormwater Infiltration Policy
Urban stormwater capture and infiltration may not be prioritized by some stormwater management agencies due to confusion caused by unclear and inconsistent regulations and unclear standards for infiltration projects. Supporting stormwater management agencies in prioritizing stormwater capture and groundwater recharge as a method of increasing water supplies is an important component of diversifying and improving California’s water supplies. This Statewide Urban Stormwater Infiltration Policy will contain a risk based framework for urban infiltration projects to provide clear, science-based direction on urban stormwater infiltration best practices while protecting groundwater quality and beneficial uses. The risk-based framework will take into consideration groundwater beneficial uses, existing site conditions such as soil characteristics, geology and geotechnical information, land uses, expected pollutants based on land use, and pretreatment system selection and design criteria.
Project Contact Information
Kelly.Rodman@Waterboards.ca.gov
(916) 323-0882
Stormwater Planning Unit
State Water Resources Control Board
1001 I Street, 15th Floor
Sacramento, CA 95814
What's New
- Public Workshops for the Proposed Urban Stormwater Infiltration Water Quality Control Policy recordings
- Save the Date! CEQA Scoping Workshop for the Proposed Urban Stormwater Infiltration Water Quality Control Policy on March 12, 2025
- Public Notice
- Written comments related to CEQA scoping due by noon on Monday, March 31, 2025.
- Informal Public Comment Period February 3, 2025 – February 25, 2025. See Staff Workshop Public Notice for details
- Save the Date! Public Workshops for the Proposed Urban Stormwater Infiltration Water Quality Control Policy on February 3, 2025 and February 6, 2025
- Urban Stormwater Infiltration Policy Factsheet (English | Español)
- Subscribe to the project mailing list to receive updates in your inbox.
Project Description
Background
Growing populations, climate change, and increased development have exacerbated water supply shortages for municipalities in semi-arid landscapes, which also tend to experience negative impacts to surface water quality from urban stormwater runoff. As municipal water supplies have become increasingly stressed, cities have begun to view capture and use of urban stormwater runoff favorably as a method of increasing water supplies while protecting surface water quality.
In California, the severe statewide droughts beginning in 2012 caused policy makers to take a closer look at all available water resources, including stormwater. The 2022 California Water Supply Strategy sets forth a goal to increase the annual water supply by 500,000 acre-feet by 2050 through supporting urban stormwater capture projects specifically.
Stormwater is a valuable resource because the capture and use of stormwater can provide multiple benefits to watersheds, including improved municipal water supply resiliency. Groundwater recharge via stormwater infiltration is a viable option for storing harvested stormwater long term, especially in the semi-arid climates occurring in many regions of California. However, a lack of a cohesive regulatory framework and a lack of clarity about water quality objectives related to stormwater capture and infiltration are obstacles to wide-scale implementation of stormwater capture and use. Stormwater infiltration projects will continue to be constructed by permittees to meet permit requirements and replenish groundwater resources in drought-stricken areas. Therefore, it is important to develop policies, guidance, and best practices that protect groundwater quality for all applicable beneficial uses, while encouraging the implementation of stormwater infiltration projects.
Project Objective
This project will result in a State Policy for Water Quality Control for urban stormwater infiltration (Policy). The proposed new Policy will encourage infiltration of urban stormwater to increase groundwater recharge and strengthen local water supply resiliency, provide greater protection to surface water quality, and develop projects with multiple benefits for communities. The Policy will also prohibit infiltration under inappropriate conditions where beneficial uses of groundwater may be impacted.
The Statewide Urban Stormwater Infiltration Policy will contain a clear, risk-based approach to encourage implementation of urban stormwater capture and infiltration projects.
Project Benefits
- Provide clear science-based direction on urban stormwater infiltration best practices.
- Protect groundwater quality and beneficial uses.
- Identify data gaps and recommend next steps to address those gaps.
- Protect surface water quality by infiltrating of stormwater runoff that would otherwise discharge to surface waters.
- Address regulatory inconsistency in current permits and local ordinances that results in confusion about where, when, and how to implement stormwater infiltration projects.
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