LOS ANGELES, Calif., Sept. 12, 2001 — People in portions of three Southern California counties may currently or soon notice a musty taste and odor in their tap water, but it is an aesthetic problem and not a health hazard, according to water-quality experts.
In making today's announcement, officials at the Metropolitan Water District of Southern California and the state Department of Water Resources stressed that the unpleasant taste and odor affecting tap water in eastern Los Angeles, western Riverside and western San Bernardino counties is not related to Tuesday's terrorist activities.
"The earthy taste and odor stem from an especially large and persistent algal bloom in the California Aqueduct along the east branch of the State Water Project north of Silverwood Lake in the San Bernardino Mountains," said Jill T. Wicke, Metropolitan's manager of water systems operations.
The taste-and-odor problem may persist through the week, Wicke said. She suggested refrigerating drinking water to help improve its taste until the problem diminishes.
Early this morning, DWR water quality experts applied copper sulfate to the east branch of the 444-mile California Aqueduct to control the algal bloom. A second copper sulfate treatment is scheduled for Thursday (Sept. 13).
DWR officials stressed that the treated water will be safe for consumers as well as boaters and swimmers downstream at the state's Silverwood Lake and Lake Perris. Fish and wildlife also will not be impacted.
"People will not notice a difference in the lake at all," said Dan Peterson, chief of DWR's environmental assessment branch.
The cause has been identified as 2-methylisoborneal, or MIB. The compound MIB is produced from the growth of certain algae in freshwaters throughout the world. Typically, MIB levels increase in summer months when the warmer weather accelerates the growth of algae, Wicke said.
"Metropolitan receives a major portion of its water through the state project's east branch and Silverwood Lake, and we are working with the state Department of Water Resources — which owns and operates the state system — to address the problem," MWD's Wicke said.
"Unfortunately, MIB is a noticeable needle in the haystack," she added. "People with sensitive taste and smell can detect the compound in water levels as low as five parts-per-trillion. However, treated water from our Mills Filtration Plant in Riverside, which exclusively receives state project supplies, has had MIB concentrations as high as 21 parts-per-trillion.
"By comparison, one part-per-trillion is equivalent to just 10 drops of MIB in enough water to fill the Rose Bowl," Wicke said.
Metropolitan member- and subagencies impacted by the problem include Three Valleys Municipal Water District in eastern Los Angeles County; Cucamonga County Water District and the Upland-based Water Facilities Authorities in western San Bernardino County; and Western and Eastern municipal water districts in western Riverside County.
Consumers interested in receiving additional information about the quality of Metropolitan's drinking water supplies may call 800/422-9426 or visit MWD's Web site, www.mwdh20.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 17 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 water-management programs. For more about these programs, visit MWD's Web site: www.mwdH2O.com.
