Here's Why SD County Tap Water Tastes, Smells Musty and Earthy

Consumers in San Diego County may be noticing a musty taste and odor in their tap water, but it is an aesthetic problem caused by algae blooms and not a health hazard, the Metropolitan Water District of Southern California announced today.

Officials at Metropolitan said the taste-and-odor situation may improve by the end of the week, as the district isolated the affected facilities and treated supplies over the weekend. In the meantime, they said, the drinking water impacts will continue to vary as local agencies blend imported Metropolitan water with local supplies.

"The earthy taste and smell stem from an algae bloom in Diamond Valley Lake near Hemet in southwest Riverside County, which is affecting supplies being delivered to the San Diego County Water Authority," said Jim Green, Metropolitan's manager of water system operations.

"Consumers, however, can be assured that the taste-and-odor issues they may be experiencing in their tap water do not pose any health risks," he said. "Consumers affected by this situation may consider refrigerating their tap water to help improve its taste until the problem diminishes."

Over the weekend, Metropolitan isolated Diamond Valley Lake and treated the algae bloom, which also has impacted untreated supplies in nearby Lake Skinner. Diamond Valley Lake and Lake Skinner are currently providing raw water to SDCWA.

MWD stressed that the treated water is safe for consumers and that fish and wildlife will not be impacted.

Growth of algae in open surface reservoirs is generally a seasonal problem that usually occurs in warm months. As in previous years, the cause of this year's taste-and-odor episode has been identified as geosmin, a nuisance compound produced from the growth of certain algae in freshwaters throughout the world, according to Green.

"Unfortunately, people with sensitive taste and smell can detect the compound in water at levels as low as 5 parts-per-trillion," he said. "By comparison, one part-per-trillion is equivalent to just 10 drops of geosmin in enough water to fill the Rose Bowl."

The Metropolitan Water District of Southern California is a cooperative of 26 cities and water agencies serving nearly 19 million people in six counties.

—City News Service

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