Water quality: permits.

Assembly Member Papan's water quality legislation directs the State Water Resources Control Board to establish a statewide permitting system for commercial, industrial, and institutional properties with five or more acres of impervious surface. The new National Pollutant Discharge Elimination System (NPDES) order would regulate stormwater runoff from these properties, which studies have linked to elevated levels of metals, sediments, and other pollutants in California waterways.

The bill requires the State Board to publish draft permit requirements by December 2028 or within 18 months after reissuing the current industrial stormwater permit, whichever occurs later. These requirements must include multiple compliance pathways for regulated entities, such as installing green infrastructure or implementing stormwater capture systems either onsite or through agreements with local municipalities. The State Board must simultaneously develop standardized rules for these offsite compliance arrangements between property owners and municipalities.

To streamline regulation, properties covered under the new statewide order would not face duplicate permitting requirements for the same facility. The legislation specifies that all applicable stormwater-related effluent limitations must be incorporated into this single permit, though construction-related stormwater discharges remain separately regulated. This consolidated approach aims to create consistent standards while maintaining flexibility in how regulated entities achieve compliance.