Amid the fourth year of drought, East Bay Municipal Utility District (EBMUD) has announced that going forward there could be a change in the taste and smell of its tap water.
"Our water this year may taste and smell different than what we are used to. It's not ideal. But the alternatives are much worse," EBMUD general manager Alexander R. Coate said in a statement Thursday.
All tap water EBMUD delivers to customers will continue to meet or exceed state and federal public health standards, EBMUD officials said.
The district's water service area includes Danville, parts of San Ramon, and unincorporated communities of Alamo, Blackhawk and Diablo.
EBMUD's water supply usually comes from snowmelt and runoff in the Mokelumne River watershed and is stored at the Pardee and Camanche reservoirs in the Sierra. This year, the Mokelumne River supplies are critically low, according to district officials.
Due to state and federal regulations, the cold water sitting deep in the Pardee reservoir must be stored all summer and released downstream in the fall to improve river conditions for returning salmon, officials said.
In order to preserve the cold water at Pardee and manage the East Bay's water supply, EBMUD must switch to a higher intake valve, pumping water that's closer to the surface of the reservoir which is warmer and typically has more algae than the deeper water, officials said.
"We will put the Mokelumne River ecosystem at risk later this year if we don't take water from a higher valve in Pardee, and we would have to take drastic measures like banning outdoor water use across the entire service area all summer if we don't draw water from the Sacramento River this year. Those alternatives are even tougher to swallow," Coate said.
The valve change is set for this Sunday (May 10) and the surface water will begin to flow to two-thirds of East Bay taps starting next week, officials said.
As of last month, EBMUD has also started filling the San Pablo and upper San Leandro reservoirs with a two-month supply of water from the Sacramento River.
The local water supplier is currently negotiating for an additional two-month supply of Sacramento River water to sustain the East Bay reservoirs over the next several months. About one-third of EBMUD's customers are already receiving water retained from that supply.
The taste and smell changes in East Bay tap water are partly due to the difference in water chemistry from the Sacramento River and water from the surface of the Pardee reservoir, according to EBMUD officials.
In addition to the operational changes EBMUD is making, greater algae growth in water reservoirs will contribute to the taste and smell shift in tap water, they said.
According to EBMUD officials, the district has five water treatment plants in the East Bay, but only two of them have aeration and ozonation equipment to improve the taste and smell of water.
The other three plants -- located in Walnut Creek, Orinda and Lafayette -- were built to treat water from the Mokelumne River which has never previously required aeration and ozonation treatment, officials said.
EBMUD expects that the plants will not be able to fully reduce the taste and odor compounds associated with algae.
Coate said planned capital improvements are in progress at some treatment plants but the district can't build more treatment fast enough to make a difference in the new taste and smell customers could experience this year.
EBMUD suggests customers chill their water or use a carbon filter before drinking to improve the taste and smell.