As California faces the prospect of a fourth consecutive dry year, officials with the Metropolitan Water District of Southern California have declared a regional drought emergency and called on water agencies to immediately reduce their use of all imported supplies.

The decision from MWD’s board came about eight months after officials declared a similar emergency for 7 million people who are dependent on supplies from the State Water Project, a vast network of reservoirs, canals and dams that convey water from Northern California. Residents reliant on California’s other major supply — the Colorado River — had not been included in that emergency declaration.