Boiling and bleaching drinking water temporarily became the norm for residents in parts of South County after routine water testing detected potentially harmful bacteria in the local water distribution system.
According to San Luis Obispo County Public Works Department spokesperson Shelly Cone, the county collected samples from 13 locations in the Lopez Lake distribution system on April 28. The test results that arrived on April 29 showed five sites tested positive for total coliform bacteria, including one also testing positive for E. coli.
“E. coli in drinking water can indicate recent sewage or animal waste contamination,” Cone said. “Ingestion of E. coli-contaminated water can lead to symptoms like diarrhea, stomach cramps, and nausea. Public water systems are required to notify consumers if their water may be unsafe.”
The presence of coliform bacteria, on the other hand, doesn’t necessarily mean the water is unsafe but triggers further testing to rule out the presence of harmful pathogens.
County officials immediately notified the California State Water Resources Control Board and began retesting the system. On April 30, the next set of results showed two sites tested positive for total coliform but negative for E. coli. The water board required the county to issue a boil water order because of the continued presence of total coliform.
The order to boil water or bleach it became active the evening of April 30 on the Public Works website, with 4th District Supervisor Jimmy Paulding sharing the notice in his periodic newsletter. The order encompassed Arroyo Grande, Grover Beach, Oceano, Pismo Beach, Avila Beach, and San Miguelito Water Company.
“This is the first time a boil water notice has been triggered for the Lopez distribution system, and we are still working to identify the cause,” a public notice from May 1 read.
Gradually, officials determined the water was safe to drink through repeated sample testing. The county lifted the boil water notice for all communities by May 3. County residents can sign up for the alert system at alertslo.org or prepareslo.org/en/public-alerting.aspx.
But boiling and bleaching water wasn’t feasible for everyone. On May 1, Arroyo Grande’s Banner Coffee Co. resorted to buying bottled water to prepare beverages using a special espresso machine.
“We can’t operate like this for three or four days, really one more day is all we can do,” Banner Coffee co-owner Ben Crandall said. “All the stores are sold out of water.”
Crandall told New Times that he first heard about the boil water notice on the night of April 30 via Instagram. While Banner Coffee’s machines boil water at very high temperature, Crandall learned that anything that comes in contact with city water isn’t to be used.
By the morning of May 1, an email from the Department of Public Health told him the business could operate on bottled water. At $1 a gallon, Crandall said Banner Coffee spent $50 that morning on ice and Crystal Geyser bottled water.
The water contamination resulted in them serving half the usual number of customers, he said.
“All restaurant owners should be getting a call from the county,” he said. “It’s crazy that I learned about this from Instagram. You have to check a couple of things to find out about the seriousness of the issue.”
Public Works’ Cone said that while the Lopez Water Treatment Plant continues to meet state and federal standards, the county is now taking extra precautions.
As of May 5, the county retested the pipeline and water at multiple locations; reviewed water quality parameters at each site; audited laboratory procedures; inspected for leaks, backflow issues, and cross-connections on the Lopez distribution pipeline; and scheduled a full assessment of the treatment and distribution systems with the state water board on May 2.
The Lopez distribution pipeline will also switch to a stronger disinfectant—free chlorine—for a few weeks.
“We also performed pipeline flushing and maintained residual disinfectant, chloramine, throughout the distribution system,” Cone said. “Disinfection, through chlorination or chloramine, eliminates harmful bacteria.” Δ
This article appears in May 8-18, 2025.