Boil-water order lifted for all remaining SLO County areas
San Luis Obispo County lifted the boil-water order for all remaining areas on Saturday afternoon, following a water-contamination alert that lasted four days.
According to an alert from the county, the boil-water order was lifted shortly after noon, allowing residents in Pismo Beach and Avila Beach to resume normal water use, after the State Division of Drinking Water gave the all-clear.
“After extensive testing, the drinking water supply has been confirmed safe,” the county said in its news release.
“Residents can return to using their tap water for ordinary purposes without taking any further action,” it added. “Restaurants can return to normal operations if they follow Environmental Health Department guidance.”
The county advised residents and businesses with reverse osmosis systems to refer to their user manual for instructions on how to safely resume using the system.
The county said it was working with state officials to investigate the cause of a single positive E. coli test result that spurred the boil order. The investigation is expected to take 30 days.
Director of Public Works John Diodati said the drinking water is safe and will be monitored and tested as the county investigates the cause.
“I recognize the last few days have been extremely impactful for our Five Cities communities. We take our mission to provide you clean and drinkable water very seriously and when there is an issue, our team immediately jumps into action to keep you safe. That is exactly what happened this week. Normal testing protocol caught a problem, and through strong collaboration and coordination with the state, cities and community service districts we were able to quickly implement preventative safety measures,” Diodati said. “Like you, we want to know why this happened. Over the next few weeks, as the investigation unfolds, we will share information with the public on what we know and what measures we will take to prevent this from happening again.”
District 3 Supervisor Dawn Ortiz-Legg also emphasized the effort that went into the alert and testing.
“Our county and cities teams have worked diligently alongside state officials to ensure the safety and quality of our water supply,” she said. “We appreciate the community’s patience and cooperation. This health and safety incident underscores the importance of people getting proper information, and we urge signing up for notifications at Public Alerting — San Luis Obispo County.”
Boil-water order affected 50,000 people
Wednesday’s boil-water order encompassed around 50,000 San Luis Obispo County residents and said that all water used for drinking and food preparation should be boiled or purified using bleach or water purification tablets through Sunday.
The order was instituted in response to the “unprecedented” detection of coliform bacteria in the Lopez water distribution system.
Coliform bacteria, the contaminant first identified in the Lopez distribution system, is an indicator of the potential presence of E. coli, county Department of Public Works public information specialist Shelly Cone told The Tribune on Thursday.
E. coli is a particular strain of fecal coliform bacteria that can cause illness in humans.
Cone said the county had not detected E. coli specifically since Monday, and was working with the state to identify the cause of the contamination.
A second sample taken on Tuesday found only elements of total coliform bacteria, not E. coli, Cone said. Though E. coli hadn’t been detected since Monday, the initial positive for both coliform and E. coli bacteria triggered the boil water notice, she said.
“The presence of coliform does not necessarily mean the water is unsafe, but it does trigger further testing to rule out the presence of harmful pathogens,” Cone said in an email. “If coliform or E. coli is detected, follow-up sampling is immediately conducted until no evidence of contamination remains.”
The boil-water order created widespread impacts across the area, shutting some food-service business, forcing others to adopt safety protocols and prompting a run on bottled water from local grocery stores.
On Friday, the order was lifted for Arroyo Grande, Grover Beach, Oceano and for customers of the San Miguelito Mutual Water Co., before the remaining communities were cleared on Saturday.
For more information on the alert, visit ReadySLO.org/WEA.
This story was originally published May 3, 2025 at 12:35 PM with the headline "Boil-water order lifted for all remaining SLO County areas."
