Laurie Weber, director of the California Water Quality Monitoring Council, opened the Nov. 20 meeting with a focus on post‑fire water quality and invited State Water Board staff to explain how the Division of Drinking Water (DDW) responds when wildfires impact service areas. "Our goal is to get people safe drinking water as soon as feasible after fires occur," Andrew (Division of Drinking Water) said in his introduction.

DDW staff described a pattern that has emerged since the 2017 Tubbs and the 2018 Camp Fire: in some incidents, combustion byproducts and volatile organic compounds (VOCs) can enter depressurized service lines and adhere to pipe materials or debris, producing localized contamination. "Benzene is by far the most prevalent contaminant that shows up over an MCL," a DDW presenter summarized, noting California sets benzene’s MCL at 1 part per billion (ppb) compared with the federal MCL of 5 ppb.

The agency explained how it conducts emergency coordination and sampling. Jason Spots (security and emergency management, DDW) described the initial response steps: information gathering, spinning up district coordination, liaising with local emergency managers and mutual‑aid groups, and identifying potentially affected public water systems using GIS layers. DDW typically asks systems to use method EPA 524.2 (modified for distribution‑system and service‑line sampling) and to collect first‑draw samples after a stagnation period (commonly 72 hours) from service taps or specially constructed risers. Laboratories performing these analyses must be ELAP‑accredited and upload results to the California Laboratory Intake Portal (CLIP), which the state uses to monitor results and which is publicly accessible.

Sean McCarthy (DDW Southern California) reviewed the Division’s work after the January 2025 Palisades and Eaton fires. Nine community water systems in that event collected more than 1,500 VOC samples in the weeks after the fires; roughly 12% of samples had at least one VOC detected and benzene appeared in about 8% of samples. DDW staff said 80 samples exceeded California’s benzene MCL and the highest single benzene result reported from the LA events was 440 ppb; earlier events (Santa Rosa/Tubbs) recorded far higher localized peaks (reported as high as 40,000 ppb in isolated service‑line samples). The Division emphasized that contamination is often localized to damaged service lines or short pipeline segments rather than a systemwide contamination.

Sampling strategy and timing matter. DDW staff told the council that stagnation before sampling (commonly 72 hours) is used to increase the chance of detecting low‑level contamination that might otherwise be missed. At the same time, DDW and water systems aim to repressurize and flush the distribution network quickly so that customers regain safe water; those operational steps can alter the distribution hydraulics and the appearance of VOCs in subsequent samples. "A sample is a snapshot in time," Yvonne (presenter) said, cautioning that early post‑fire samples can look different from samples taken after flushing and repairs.

When benzene or other concerning VOCs are detected, DDW may require additional testing, prescribe flushing or remediation measures, require customer notification, and use its authority under Assembly Bill 541 (signed by the governor Oct. 8, 2023; codified in California Health & Safety Code §116596 and effective Jan. 1, 2024) to order benzene testing when specified conditions are met (fires over 300 acres with damaged or destroyed structures connected to the water system).

The council heard practical lessons from the field: systems with quick repressurization and thorough flushing tended to report fewer persistent detections, while systems that took weeks to isolate broken service lines and restore pressure saw more detections and required iterative flushing and resampling. DDW staff also noted resource pressures: large utilities like LADWP had internal lab capacity and operator staff, while smaller mutual water companies relied on mutual aid and subcontracted labs. Christine Sotelo (ELAP) described how ELAP works with DDW to identify lab capacity and support surge needs among the roughly 500 accredited laboratories in California.

DDW and the Monitoring Council framed next steps as a mix of operational guidance and research: maintaining and improving sample‑plan templates (including clear data‑quality objectives and reporting paths to CLIP), investing in research to explain why some service lines become contaminated while adjacent lines do not (factors include burn intensity, pipe material and thermal exposure, system hydraulics and timing of depressurization), and expanding prebuilt sampling resources that water systems can use during recovery.

DDW reiterated its public‑health priority: precautionary "do not drink / do not boil" notices are used where needed because boiling does not remove VOC inhalation risks, and lifting such notices requires evidence from repeated rounds of appropriate sampling and remediation. The council discussed potential roles it could play: helping assemble sample‑plan templates, coordinating data‑quality advice, and connecting smaller systems to mutual‑aid and lab capacity resources. The meeting closed with agreement that the post‑fire monitoring work group and council pages could host and curate guidance and data links for future incidents.

Ending: DDW will continue to refine sampling and recovery guidance as research and field experience evolve; AB 541 gives the Division explicit authority to require and oversee benzene and other post‑fire testing where the statute’s conditions apply.