Grover Beach rescinds boil-water notice after Lopez pipeline bacteria tests; county investigation continues

Grover Beach City officials told the City Council on May 12 that a boil-water notice issued for the Lopez pipeline in late April was rescinded after the city’s own drinking-water samples remained negative and the city temporarily disconnected from the pipeline.

Public Works Director and City Engineer Greg Ray said the county of San Luis Obispo notified downstream agencies on April 29 that routine sampling had indicated bacteria in the Lopez pipeline. Ray said the state Division of Drinking Water directed the county and connected agencies on April 30 to issue a boil-water notice under state testing rules.

Ray explained why the notice was required: “state law requires that if a water system has two routine sampling, two routine samples for bacteria that test positive and any of those samples indicate the presence of the E. coli bacteria, the water system must issue a boil water notice.” He said one of 13 routine samples taken by the county on April 28 indicated the presence of E. coli. Follow-up county tests on April 29 and April 30 still showed bacteria at two locations in the pipeline, Ray said.

Ray told the council the city’s own water samples taken April 28–30 showed no bacteria. After receiving the county’s results, the city disconnected from the Lopez pipeline while conducting daily testing; Ray said those city tests came up negative and “the state did allow the city to rescind the boil water notice.” He added that agencies that could not disconnect from the Lopez pipeline had to wait until the county rescinded its notice.

The county and state remain engaged in an active probe of the Lopez pipeline. Ray told the council the county audited the pipeline and “has now switched to a stronger disinfectant,” and that the county and state continue vigorous testing and inspection to determine the cause of the positive samples. Ray said the cause of the bacteria is unknown.

City staff described the operational steps taken during the incident: immediate disconnection from the Lopez pipeline; increasing sampling frequency from monthly to daily; coordinated alerts through the county Office of Emergency Services and the city’s billing and emergency notification systems; updates on the city website and social media; and public service announcements produced by the mayor. Ray urged residents to sign up for the county’s public alert system and to keep utility contact information current, pointing listeners to the county’s public alert web page.

Council members asked technical and procedural questions. One council member asked whether reverse-osmosis (RO) systems remove E. coli; Ray said RO systems are generally “very effective” but the city cannot verify the condition or maintenance of individual filters, and that county guidance during a boil-water notice may still recommend boiling even for customers with RO systems. Members also asked whether the city’s groundwater supply could sustain the community if the Lopez connection remained offline; Ray said current conditions suggested the city could remain on groundwater for a substantial period.

Ray concluded that the city has reconnected to the Lopez pipeline but continues rigorous testing to ensure water safety. He directed residents to the county web page listed by staff for the latest updates and to sign up for public alerts.

The council did not take formal action on the update; council members and several residents praised staff’s communication and response.