GARDENA (CBS) — A musty taste and odor to the tap water in four Southern California counties originally projected to last only a few weeks has persisted for six months now.
Metropolitan Water District officials say the odd taste to the tap water is an aesthetic problem due to an especially large and persistent algae bloom in the east branch of the State Water Project, which includes Silverwood Lake in the San Bernardino Mountains.
The algae bloom produces 2-methylisoborneal, or MIB, and levels of the compound increase when warmer weather accelerates the growth of algae. MIB causes the water to have that musty smell and taste.
Water quality experts have been applying copper sulfate to control the algae bloom. Metropolitan also says they have reduced deliveries from Silverwood Lake, which supplies two plants that provide treated drinking water to about 7 million people in the affected area.
“Unfortunately, MIB is a noticeable needle in the haystack,” said Jim Green, Metropolitan’s manager of water system operations, in a statement. “People with sensitive taste and smell can detect the compound in water levels as low as 5 parts-per-trillion. However, water from two treatment plants have experienced MIB concentrations as high as 20-parts-per-trillion.”
The affected tap water stretches from eastern Los Angeles County communities to Orange County and from western San Bernardino to southwest Riverside counties. The musty taste and smell varies from region to region because local agencies blend imported Metropolitan water with local supplies.
The Metropolitan Water District first acknowledged the earthy-smelling and – tasting water in September, but consumers continue to complain about the problem.
Officials say the water is not a health hazard, and that refrigerating the water can help improve the taste until the problem diminishes.