Assessing the Microbial Risks and Impacts from Stormwater Capture and Use to Establish Appropriate Best Management Practices

Stormwater capture and use (SCU) offers a wide range of benefits, including enhancement of local water supplies, combined sewer overflow reduction, and stormwater runoff volume and pollutant load reduction. However, implementation of stormwater use projects is not widespread due to lack of regulatory frameworks (including consistent water quality targets) and design protocols. There is a critical need for guidance on appropriate risk-based treatment levels for non-potable and potable uses to ensure stormwater use projects are protective of public health.

This project synthesized existing research on stormwater microbial quality and treatment processes to develop a Stormwater Use Roadmap that provides pragmatic guidance for design and operation of SCU systems. The guidance addresses selection of appropriate log reduction targets based on quality of stormwater and intended end use, methodologies for monitoring stormwater microbial quality, and approaches for continuous monitoring of operational systems to ensure safe water is reliably delivered for utilities and municipalities. Published in 2023.