The Sacramento Bee reported Thursday that the San Juan Water District board of directors approved the move this week.
The district serves more than 265,000 people in the Sacramento suburbs, including the communities of Citrus Heights, Orangevale and Folsom.
Most of its water comes from Folsom Reservoir, which the newspaper says has shrunk perilously low amid one of the driest winters in California history.
District General Manager Shauna Lorance says the call for conservation is not mandatory, but it could become so next month if the area doesn't get rain soon.
The district also is extending a request for a 20 percent cut in all water use that has been in place for months.
The U.S. Drought Center says the past week brought "widespread improvements" in drought conditions in northern California and Nevada.
California's energy grid manager says supply should be adequate for the summer, despite potential natural gas shortages in Southern California.
California water regulators will allow cities and water agencies to set their own conservation targets based on water supply.
Fire agencies are expected to continue prescribed burn operations this week in the Lake Tahoe Basin.
Severe and extreme drought were reduced slightly in California and 10 percent of the state is completely free of drought.