Scores of California farmers, irrigation districts and small communities that hold some of the strongest rights to water from rivers and streams received far-reaching orders Friday to stop pumping, the latest effort by state water officials to protect diminishing supplies amid the four-year drought.

The notice issued by the California Water Resources Control Board affects water rights holders with claims dating between 1903 and 1914 in the Sacramento River watershed, the San Joaquin River watershed, and the Delta to halt diversions. Those with rights established later have already been curtailed.

Under state laws that have drawn increasing scrutiny, water in California’s mountain-fed rivers and streams is divvied out in order of seniority. Only once before — in the late 1970s — have state water officials leveled cuts on water rights holders with claims prior to 1914, the year the state first began tracking water use....

Friday’s curtailment order applies to 276 pre-1914 water rights holders, which include individual property owners, irrigation districts, hydroelectric facilities and at least two communities that provide drinking water — in Nevada County and Plumas County, according to state officials.