The State Water Resources Control Board on Nov. 19 voted to adopt statewide regulations for on‑site treatment and reuse of nonpotable water required by Senate Bill 966.

Shirley Rosalella, the technical lead, said the rules are risk‑based and were developed with an expert panel convened by the National Water Research Institute to set pathogen log reduction targets for multiple source waters and end uses. "These regulations are risk based as mandated by the senate bill and are focused on protection of public health," she said.

Staff described a yearlong rulemaking process that included a 45‑day comment period, a public hearing and a 15‑day supplemental comment period. Revisions included a streamlined process for approving alternative treatment trains, added notification requirements for water and sewer providers during commissioning and decommissioning, and relaxed signage options consistent with Title 22.

During public comment, multiple stakeholders urged clarity on how the rules apply to stormwater capture, large regional stormwater projects and existing on‑site systems. Richard Ross of EPIC CleanTech asked how existing systems will be treated and urged clear interim guidance; Marty Farwell and Patrick McDonough of advocacy groups warned the prescriptive criteria could make some stormwater capture and reuse projects economically infeasible.

Staff responded that the regulations are narrowly targeted to building‑scale on‑site reuse and that rainwater and graywater systems subject to California building standards are excluded. Darren Pelhamis of the Division of Drinking Water said the agency is working on separate processes for large, mixed stormwater projects and will not apply these building‑scale regulations to projects outside that narrow definition.

A motion to adopt was made and seconded. The clerk called roll and Vice Chair Doreen D'Adamo, Board member Nicole Morgan, Board member Laurel Firestone and Chair Joaquin Esquivel each voted 'Aye.' The board adopted the regulations. Staff said implementation will require local jurisdictions to adopt local ordinances and coordinate with the Department of Housing and Community Development on building standards. Next rulemaking for foundation drainage and cooling towers was noted as required by recent legislation and is planned for early 2028.