The cloudy water some Manhattan Beach residents and businesses may have seen Wednesday morning did not pose a safety issue, said Utilities Manager Raul Saenz, explaining that the typical sediment of calcium, magnesium and iron found at the bottom of the city's water pipes was stirred up by the amount of pressure generated on the water system when a fire hydrant was knocked off Wednesday at Highland Avenue and 45th Street.
"It's not like mud was in the system," he said. "It's more of an aesthetic thing really. We would not advise that people drink it but from a technical perspective and as a chemist, what people were seeing is in their normal water in soluble form."
The city's water system was stirred up when a fire hydrant was sheared off, causing crystallized sediment that usually accumulates at the bottom of pipes to become buoyant, said Saenz, hence the cloudy water people saw when turning on their faucets.
The pressure caused by the knocked off hydrant "exceeded the design flows of the pipelines," he explained, with the "velocities through the pipelines" greater than during regular use. The pipes were "scoured by full velocity."
Neither Saenz nor Manhattan Beach Fire Department Battalion Chief Ron Laursen, who was not on duty during the 6 a.m. incident, knew why the hydrant had been knocked off.
Laursen said it took fire personnel about an hour to stop the water, which was gushing three-stories high into the air, because "with all the water shooting straight up and back down on top [of the firefighters] it was difficult to get the cap off and then to get to the [shut-off] valve."
City water department crews then flushed pipelines. Their work plus the passage of time during which sediment calms down combined to put the water system back at its normal operation.
Saenz said the city water system is monitored "24/7, real time, all the time" and the entire water system is flushed once a year. He said the city water system has a "chlorine residual disinfectant in the water at all times."
- Previously: Residents Advised to Run Water Until 'Clean'