New Delhi, Aug. 1 -- WASHINGTON - In Gilbert, Arizona, water bills climbed 50 percent between April 2025 and this summer, and a federal proposal unveiled Friday signals the upward pressure on costs across the American Southwest has barely begun.

The United States Bureau of Reclamation on Friday proposed mandatory reductions of up to three million acre-feet annually in Colorado River water use for Arizona, California, and Nevada through 2036, establishing the sharpest federal demand for cuts in the modern history of a waterway that supports more than 40 million people across seven states, Mexico, and dozens of tribal nations. Binding operating guidelines are expected by October 1.

Interior Secretary Doug Burgum said Friday the department...