Algae growth in a Hesperia lake is causing tap water delivered to residents in Los Angeles, San Bernardino and Riverside counties to taste and smell musty.
Officials with the Metropolitan Water District of Southern California advised residents not to be alarmed by the earthy odor and taste, which they said was an "aesthetic problem and not a health issue."
Consumers "can be assured that the taste-and-odor issues they may be experiencing in their tap water do not pose any health risks," Jim Green, the district's manager of water system operations, said in a statement.
Water from Silverwood Lake in Hesperia is delivered to customers in eastern Los Angeles, western San Bernardino and southwest Riverside counties. From there, the water is blended with supplies from local agencies, so the taste and odor may vary.
Algae growth is a seasonal problem, typically occurring in the summer months, according to the MWD.
Geosmin, which is produced from the growth of freshwater algae, was identified as causing the odor and taste, officials said.
The state Department of Water Resources plans to treat the algae growth next week.
In the meantime, customers are advised to refrigerate their water to improve the taste.