State Water Board holds hearing on proposed on-site nonpotable reuse rules; public commenters press for operator certification and Title 22 alignment

Shirley Rossella, senior staff with the Division of Drinking Water at the State Water Resources Control Board, outlined proposed statewide regulations for on-site treatment and reuse of nonpotable water at a public hearing and invited public comment on the draft. The rules would set risk‑based water quality standards, monitoring and reporting requirements, cross‑connection controls and treatment‑train options for building‑scale systems used for nonpotable indoor and outdoor purposes.

The regulations respond to Senate Bill 966 (2018) and codified direction in the California Water Code to adopt standards for on-site reuse. Rossella told attendees, “The proposed regulations will establish criteria for on-site treatment of non potable water for non potable reuse.” She said the State Water Board developed the rules to be “protective of public health” and noted the board cannot itself permit local installations: “We do not have the authority to permit on-site reuse systems.”

The draft regulation text presented by staff includes: risk‑based pathogen log reduction targets (LRTs) derived from quantitative microbial risk assessment; preset “pathogen control” treatment trains (examples include membrane bioreactors, membrane filtration, UV disinfection and chlorination) or a path for approval of alternative treatment trains that demonstrate equivalent public‑health protection; continuous process verification monitoring; temperature and disinfectant residual controls to limit opportunistic pathogen regrowth; and weekly disinfectant residual checks for storage and distribution systems. For example, staff identified one proposed LRT set for treated on‑site wastewater used for toilet flushing as an 8‑log virus reduction, 6‑log Giardia reduction and 5.5‑log Cryptosporidium reduction.

Rossella and Randy Barnard, technical operations section chief with the Division of Drinking Water, also described implementation steps and timelines: the board’s notice was published March 21; the public comment period closes at noon on Friday, May 9; the board’s adoption goal is Dec. 31, 2025; the board then has up to 12 months to finalize rulemaking and submit the package to the Office of Administrative Law for a 30‑day review; within 12 months of board adoption the Department of Housing and Community Development must adopt corresponding building standards to support the regulations.

During oral public comment, Greg Thomas of Elsinore Valley Municipal Water District said the systems operate like “smaller wastewater treatment plants” and urged that “we really need to have licensed operators, certified operators, manning these things because ... it's all about public health.” Thomas noted that building‑scale installations frequently use treatment technologies similar to municipal systems (MBRs, microfiltration, UV, chlorination) and urged the regulations address operator certification and cross‑connection protections.

Rosario Cortez, manager of regulatory affairs for Water Reuse California, told the board the trade association will submit written comments and recommended several clarifications. Cortez urged the board to consider alignment with existing Title 22 disinfected tertiary recycled water standards, asked for explicit language on whether operator training and certification will be required, and requested clarification on enforcement roles (local jurisdictions versus regional water boards). Cortez also asked that the regulation use the same statutory phrasing for irrigation uses and align sign visibility requirements with the California Plumbing Code.

Staff repeatedly emphasized that local jurisdictions must adopt local ordinances to permit on‑site reuse systems and that local permitting authorities must consult water and sewer utilities when the jurisdiction does not provide those services. Rossella said the statutes require local programs to include design criteria, permitting, cross‑connection control and enforcement procedures and that the State Water Board will collect annual reports from local jurisdictions summarizing new/replacement systems, source water types and quantities, end uses, and any violations and corrective actions.

No formal vote was taken at the hearing; staff recorded oral comments for inclusion in the rulemaking record and reminded attendees of the deadline for written comments. The board will respond to comments in subsequent rulemaking documents posted to its website and will consider revisions before final adoption.

The hearing combined technical regulatory detail and stakeholder concerns about operations and enforcement. Commenters asked staff to clarify operator certification, consistency with Title 22 standards, enforcement roles, the scope of allowable irrigation language, and signage requirements. Those topics appear likely to be addressed in the written comment record and subsequent rulemaking documents.