Noticed A "Musty Odor" In Your Water Lately? LADWP Says Don't Freak Out

Noticed something...off with the drinking water lately?

If what you're getting is a certain earthy aroma, the Los Angeles Department of Water and Power says that it's perfectly, uh, cool. As the department said in a release, customers in the San Fernando Valley may be noticing an "earthy or musty odor" that's caused by seasonal algae growth. That growth is especially pronounced this year, thanks to the wealth of rainfall we got over the winter season.

As Albert Gastelum, director of water quality at the LADWP, explained to LAist, the impressive levels of rain led to plenty of snow melt, which helped wash a bigger load of algae-friendly nutrients into our local waterways. "You're putting more food in there. And then you add in sunlight, and those conditions can lead to a bloom," said Gastelum

The specific culprit is a strain of blue-green algae called anabaena, which, according to the LADWP, is common and "makes an unwelcomed appearance each year during the summer season." As Gastelum told LAist, anabaena can break down and result in a number of "byproducts," some of which are toxic (like microcystin, which overtook Pyramid Lake by Castaic last summer).

After testing, the LADWP ruled out a dangerous level of toxins, and now believe that the anabaena has broken down to either geosmin or 2-methylisoborneol (MIB), which the Environmental Protection Agency describes as "not toxic but are a nuisance to the public." Geosmin, in particular, produces an earthy flavor in some foods, as well as the earthy scent we get after a downpour. A 2014 study (which has been archived at the National Center for Biotechnology Information) describes geosmin as "one of the most commonly detected off-flavor chemicals present in reservoirs and drinking water systems."

As for why it's the San Fernando Valley, specifically, that may be subjected to that musky odor, Gastelum says it's because the algae bloom happened in waters that fed into the city-owned Los Angeles Aqueduct, which services the Valley. Other parts of the L.A. area may get their water from other sources, like the Colorado River Aqueduct. "It's a roll of the dice. The blooms can happen anywhere," said Gastelum. In 2016, more than 30 lakes, streams and reservoirs in California were hit with significant algae blooms by September, reports the OC Register.

While Gastelum didn't give an exact timeframe on when we can expect the odor to end, he says the effects may be tapering off; calls reporting the musty taste had peaked earlier this week, but have been steadily decreasing since. Still, if you're noticing a peculiar taste or smell in your water, the LADWP advises that you call the agency's water quality hotline at 213-367-3182.