Jul 16, 2012

No Health Hazard from California Tap Water with Unpleasant Taste, Odor

Earthy, musty taste and smell in drinking water in two Southern California counties could persist for weeks

Some residents in parts of two Southern California counties may notice a musty taste and odor in their tap water, but it is an aesthetic problem caused by an algae bloom and is not a health hazard, according to water quality experts.

Officials at the Metropolitan Water District of Southern California said the taste and odor event is affecting tap water in eastern Los Angeles County communities, as well as southwestern San Bernardino County. The impacts may vary as local agencies blend imported water with local supplies.

"The earthy taste and smell stem from an especially large and persistent algae bloom in the east branch of the State Water Project," said Jim Green, the water district'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."

Green suggested that consumers might consider refrigerating drinking water to help improve its taste until the problem diminishes. He cautioned, however, that the problem might persist for a few more weeks.

DWR water quality experts recently applied copper sulfate, an approved method, to control the algae bloom. Officials stressed that the treated water will be safe for consumers as well as boaters and swimmers at Silverwood Lake. Fish and wildlife also will not be impacted.

The cause has been identified as both 2-methylisoborneal, or MIB, and geosmin. These compounds are produced from the growth of certain algae in freshwater throughout the world.

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

Water district member agencies that could be impacted by the problem include the Three Valleys Municipal Water District in eastern Los Angeles County and Inland Empire Utilities Agency in southwestern San Bernardino County.

Consumers interested in receiving additional information about the quality of drinking water supplies can visit the district's website, www.mwdh2o.com, for the district's annual water quality report and other related materials.