The state told the city of Poway Wednesday that the clearwell reservoir at its water treatment facility – the same reservoir contaminated by a backed-up storm drain prompting a multi-day Precautionary Boil Water Advisory – is out of compliance because of its proximity to the storm drain.
The notice came as a shock, according to the city, because regular facility inspections by the California State Water Resources Control Board (CSWRCB) over the last 50 years, and as recent as September, uncovered no similar compliance issues.
The reservoir is the final container system for filtered water at the Lester J. Berglund Water Treatment Plant near Lake Poway. When the reservoir is at risk of overflowing, a door opens to let water flow out into a storm drain. That overflow door malfunctioned over the weekend and became stuck open, according to the city.
Meanwhile, the storm drain had become clogged amid a strong three-day storm that dumped rain on the county over the Thanksgiving holiday. Contaminated water from the storm drain was then allowed to spill back into the reservoir and contaminate the city’s water supply.
Residents reported discolored water from their taps on Friday and the boil advisory was issued the following day. As of Wednesday the city was still waiting on the state to lift the advisory.
Under the advisory, residents were told to boil their tap water prior to consumption, and most restaurants and food services businesses were ordered to close.
The compromised reservoir was built in the 1960s, likely at a time when engineers weren’t required to separate the reservoir from the storm drain system as they are now, according to Sean Sterchi of the CSWRCB.
The CSWRCB will be issuing a citation to the city of Poway “for failure to take preventable action in advance of this issue,” Sterchi said.
The issue can be solved in two ways, Sterchi said: Poway can install an air gap that will prevent backflow, or the city can submit an alternative design for the state to review.
The CSWRCB could fine the city of Poway depending on the outcome of the incident, but it’s too early o speculate if the city will be fined, according to Sterchi.
Three certified water tests showed the city’s water was absent of bacteria, the city said Thursday. And it maintains that its test results have met state standards since the advisory was put in place.
“Actually the water is well within our standards for drinking. I’m still drinkin’ it, but the State, they’re a little more skittish. Sacramento works in strange ways, so we’re giving out water to make sure our folks are taken care of,” Poway Mayor Steve Vaus told NBC 7 on Monday.
Water samples collected Wednesday and Thursday at 37 sites will be sent to a state lab for testing, the city said.
“The city continues to follow mandated state protocols for the precautionary boil water advisory,” the city said.
Restaurants must flush all water lines, purge beverage and ice machines connected to the water systems, throw away old ice, sanitize all items that may have been in contact with the water and discard all potentially contaminated food, according to the county.
The Poway Unified School District said schools would remain open Monday and authorities were taking the necessary steps to ensure student safety.