Federal water managers are setting a Jan. 31 deadline for the seven Southwestern states that depend on the Colorado River to finalize unprecedented voluntary drought contingency plans they expect to have to enact in 2020.
Otherwise, top U.S. water official Brenda Burman says the federal government will announce in August the unspecified water restrictions it will impose on users in Arizona, California, Colorado, Nevada, New Mexico, Utah and Wyoming.
The river and the huge Lake Powell and Lake Mead reservoirs provide drinking water to 40 million people and irrigation for crops in arid parts of the U.S. and Mexico.
Most states met Burman's goal to reach agreements on plans to use less water.
Burman told a water users conference in Las Vegas that California and Arizona are the holdouts.
Arizona would be first to feel the pinch if a shortage is declared as expected next year.
Supplies to Nevada and California also could be curtailed.
Arizona state lawmakers still have to approve mitigation plans, perhaps in January.