A recent dramatic drop in water conservation statewide could lead to a renewal of state-imposed mandatory water restrictions, according to California water officials.
The State Water Resources Control Board announced that conservation efforts for August 2016 dropped to 17.7 percent statewide, compared to 27 percent from August 2015, which is a decline of roughly 35 percent.
Water conservation dropped so steeply in some areas that state-mandated conservation measures could return by next year, according to board officials.
"While last year's rain and snow brought a respite for urban California, we are still in drought and we can't know what this winter will bring," board chair Felicia Marcus said in a statement.
Water officials are trying to determine a reason for the drop, with Marcus suggesting that in some cases it might be due to a lack of public outreach by some of the local water agencies and in some cases local agencies might be abandoning conservation programs altogether.
"The statewide August conservation results raise questions, and we are examining the data to understand why some areas slipped more than others," Marcus said.
The state's conservation rates are calculated based on water use baselines that were established in 2013, before the current drought really took hold.
A few Bay Area communities were singled out by the board for surpassing the state conservation average, including the Alameda County Water District, the Contra Costa Water District, the city of Hayward and the San Jose Water Company.
Some areas, including Daly City and East Palo Alto, saw a small percentage savings overall but continued to maintain low per-capita residential water use.
"The Bay Area traditionally has the lowest residential gallon usage per day," said board spokesman George Kostyrko.
A few of the local water districts that dropped from savings rates of more than 20 percent last year to single-digit rates this year include the Casitas Municipal Water District, the cities of Folsom and La Habra, the water districts that serve Malibu and Mountain House and the South Lake Tahoe Public Utilities District, according to board officials.
"We're urging (water districts) where we've seen a precipitous drop in conservation to reach out to high-use customers and urge them to conserve," Kostyrko said.
The state stopped requiring a 25 percent water savings rate in June, when conservation measures became voluntary.
• Earlier story: Cal Water gives a state-of-the-drought update.