Lake Powell was 23.4% full on July 19—its lowest level for this point in summer—and further declines could trigger “dead pool,” stopping river flow through the Grand Canyon.
Cities are tightening conservation rather than bracing for immediate drinking-water outages: Phoenix expanded purification and leak detection, Tucson says it has more than six years of stored water, and Albuquerque has halved per-person daily use since the mid-1990s.
San Diego, which depends heavily on the river, is leaning on desalination and water reuse, while Southern California's district has also paid farmers to conserve and leave some land unplanted.
The strain reaches beyond cities because most diverted Colorado River water goes to agriculture, California grows a large share of U.S. produce, and the seven basin states still lack a compromise on deeper cuts.