At 11:45 a.m. on February 23, 2023, an employee, 20, working for a city water department, was repairing a leaking 12-inch PVC waterline main valve. The valve was located in a utility vault approximately 5 feet deep. The employee turned off the water to the WEST of the valve by opening multiple fire hydrants. He and a coworker closed the valve, stopping the water from flowing from the west. The employee(s) did NOT turn the water off on the East side of the valve.
The repair work involved repairing or replacing a gasket on the west side of the valve. The employee attempted to tighten the flange, hoping the gasket would not need replacement. The bolts on the flange were corroded, and he was unable to remove the lower bolts due to water and sludge in the vault.
The employee exited the vault and waited for the vacuum truck to clean out the vault. The employee re-entered the vault and attempted to remove the bolts but did not succeed. He decided to cut the pipe with a hydraulically powered concrete cutting saw. While cutting the waterline, the concrete saw jammed, and water flowed into the vault.
