Water from a faucet in National City on April 15, 2022
Water from the faucet of a home in National City on April 15, 2022 / Photo courtesy of Ramel J. Wallace

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National City resident Ramel Wallace wanted to know what was in the apple juice-colored water that poured from his tap earlier this month, so he tested it and sent me the results.

While a water quality test purchased from Walmart is not as detailed as one taken by a hydrologic specialist at a lab, Wallace’s tests didn’t seem to show anything out of the ordinary, said Justin Brazil, Sweetwater’s director of water quality, after hearing the results read to him by a reporter.

Ramel Wallace, a National City resident who said he bought these water quality tests from Walmart, tested some of the yellow water flowing from his tap on Friday, April 15, and provided them to a reporter at Voice of San Diego last week. / Photo courtesy of Ramel Wallace

The pH (water’s acidity) of National City well water is around 7.8, Brazil said. Its hardness (a measure of dissolved minerals, specifically dissolved calcium and magnesium) is between 170 and 180 parts per million, which is fairly hard. Wallace’s test results appeared to fall within those parameters.

But Sweetwater Authority, which treats and sells drinking water to National City, Bonita and a large chunk of Chula Vista, didn’t actually test the water when it turned yellow a few weeks ago.

“It’s very, very well characterized,” Brazil said. “That’s why we didn’t perform any additional tests. And by the time we did field investigations, the water was already clearing up.”

What he means is, this happens enough at Sweetwater Authority that Brazil is confident about what caused it. That yellowed water, Brazil reiterated, is a product of the naturally-occuring minerals iron and manganese that settle-out and sit at the bottom of water mains. Those are some of the most abundant minerals in the Earth’s crust, Brazil said, and therefore make their way into water systems.

Sweetwater Authority is unique in San Diego because it gets around 70 percent of its water from local sources, like the Sweetwater River which starts in the Cuyamaca Mountains and tumbles to the Pacific Ocean, and groundwater from tapping wells into aquifers. But the rest of San Diego County gets most of its drinking water from the Colorado River.

Most of Sweetwater’s customers water travels by gravity from those mountains, but when there’s an unexpected burst of water pressure, like a busted fire hydrant or an open water main valve (which caused the latest sepia-stained tap water incident), all those minerals get mixed into the water again and appear at the tap.

“It’s kind of like a snow globe,” Brazil said. “That snow will sit at the bottom of the snow globe all the time but if you shake it up, momentarily, everything becomes suspended and eventually settles back down.”

The incident that affected Wallace’s water happened right on the boundary of an area that receives water via gravity, and another area where water is pumped up to higher elevations and stored in tanks. That high pressure flushed into that low pressure zone and bam, shaken snow globe.

Sweetwater Authority started a process of flushing those minerals from its pipes in 2019 but the COVID-19 pandemic slowed progress, said Sweetwater Authority spokeswoman Leslie Payne. Typically water main flushing means water is pumped out of a fire hydrant and lost to a stormwater drain, which is a pretty big waste of drinking water. So Sweetwater is hoping to try a new circular process where water is flushed through a filtration device that’s mounted on a truck.

“That will greatly reduce the amount of future water quality complaints in National City,” Payne said.

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3 Comments

  1. Well, since the water authority says its normal, I guess there’s no reason at all, journalistically speaking, to check with an outside expert.

    1. Again, we’re taking the water company’s word for this… seems like the bare minimum would be asking an independent expert.

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