City Manager Nathan Olson says the cause of the blast, which killed a contract worker and injured a city employee, is a mystery and still under investigation by state officials.
"Some type of a gas or something must have built up in the tank and when they went to weld, we had an explosion in the headspace of the tank," Olson said. "Well, that caused the tank to rip at the seam and lift up and then once the water came out, we could see the flash of the explosion and then the tsunami ensued."
A GoFundMe account has been set up to help the family of the fallen contractor, 41-year-old Dion Jones.
Jones was a longtime employee of a Southern California-based construction company.
He leaves behind a wife and three kids.
The injured city employee was released from the hospital the same night as the incident.
"I think the shock and awe are over now, and today we're in rebuild mode," Olson said. "And I think people are a little bit refreshed and they've rolled up their sleeves. I'm really happy with the progress we made this morning."
The explosion at the Station 7 Water Facility took three of the city's wells offline, and the loss of the tank and pumps comes with a loss of water pressure for some businesses and residents.
On Wednesday, Olson said crews were working to restart two wells so they could complete the urgent task of sending water to their new treatment tanks to avoid the high costs associated with a gap in the recycling process.
They're also working to repair a line that feeds into the other 1.5 million gallon tank that's still standing and prepare it for use again.
"Once we get that then we have to fill that tank, chlorinate it, hold 24 hours to sample, send it to the state," Olson said. "Wait another 24 hours, take another sample, so there's going to be about two to three days where we're going to have water there ready to go out but we got to wait for the testing to happen."
In the meantime, Olson hopes residents will continue to conserve water.
A local emergency proclamation prohibits all outdoor watering. As of Wednesday, no boil water notices have been issued.
Cal/OSHA released the following statement to Action News about the water tank explosion:
On June 21, Cal/OSHA was notified of a fatality involving an employee of J.R. Filanc Construction. According to the notification, an employee was fatally injured when a water tank exploded. Cal/OSHA is investigating to determine the cause of the incident and identify any violations of workplace safety requirements.