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 not a health hazard, according to water
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 Metropolitan 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, Metropolitan’s manager of water system operations.
“Metropolitan receives a major portion of its water through the SWP’s
east branch, which includes Silverwood Lake in the San Bernardino
Mountains, and we are working with the state Department of Water
Resources (DWR)—which owns and operates the state system—to address the
situation,” Green said.
“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
Green suggested consumers may consider refrigerating drinking water to
help improve its taste until the problem diminishes. He cautioned,
however, that the problem may 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 nuisance compounds are produced from the growth of
certain algae in freshwaters 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,” added Green.
Metropolitan 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
Consumers interested in receiving additional information about the
quality of Metropolitan’s drinking water supplies can visit the
district’s website, mwdh2o.com, for the district’s annual water quality
report and other related materials.
The Metropolitan Water District of Southern California is a
cooperative of 26 cities and water agencies serving nearly 19 million
people in six counties. The district imports water from
the Colorado River and Northern California to supplement local supplies,
and helps its members to develop increased water conservation,
recycling, storage and other resource-management programs.