Under existing law, the State Water Resources Control Board and the 9 California regional water quality control boards regulate water quality and prescribe waste discharge requirements in accordance with the federal national pollutant discharge elimination system (NPDES) permit program established by the federal Clean Water Act and the Porter-Cologne Water Quality Control Act. Existing law requires each regional board to formulate and adopt water quality control plans for all areas within the region, as provided.

The bill would require the state board, after making the necessary residual designation authority findings, to establish a statewide commercial, industrial, and institutional NPDES order for properties with 5 acres or more of impervious surface, as provided. The bill would require the state board to publish a draft order of the statewide order for public comment on or before December 31, 2028, or 18 months after the reissuance of a specified statewide permit, as specified. The bill would require the state board to contemporaneously establish rules for offsite compliance agreements to issue with the publication of the draft statewide order for public comment that details the necessary components of an agreement between commercial, industrial, and institutional permittees and local municipalities for achieving offsite stormwater capture and use within the adopted final statewide commercial, industrial, and institutional NPDES order. The bill would require the NPDES order to include multiple compliance options for discharges to select and comply with to be deemed in compliance with applicable water quality based effluent limitations, including, but not limited to, compliance options incentivizing green infrastructure onsite or offsite stormwater capture and use.