The Ukiah Daily Journal reports that the county's Board of Supervisors on Tuesday voted unanimously to make the declaration, citing an "imminent threat of disaster" from drought conditions.
The state Department of Water Resources said Mendocino is the first to request state drought assistance.
Officials hope the declaration will result in state funds and assistance in developing a drought plan.
Gov. Jerry Brown has convened a task force to help decide if a statewide drought emergency is warranted.
State water managers say they will be able to deliver just 5 percent of the water sought by municipal agencies and nearly a million acres of farmland.
Some areas in the Sacramento region will have to reduce water use by 36 percent under proposed emergency drought rules from state water regulators. How urban suppliers will reach that goal varies. Enforcement is likely to increase everywhere.
(AP) - State regulators are ordering some farms to stop pumping from streams for the second year in a row.
As California enters the dry season, the latest U.S. Drought Monitor report shows one category expanding.
In spite of a California Appeals Court ruling, customers of private water suppliers may still have tiered rates based on usage, not on cost, and customers of private utilities may still see their rates go up.
California Governor Jerry Brown is calling on local water agencies to adjust their pricing structures as a way to promote conservation. But a state court ruling issued today could undermine those efforts.