The questions people actually ask about Lake Mead, answered from the same cited research that grounds this Watch's chat — and the chat can go deeper on any of them.
Lake Mead at Hoover Dam is at 1038.94 ft (Power House Datum), down 1.6 ft over 30 days.
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Lake Mead is the largest reservoir in the United States by maximum capacity. At full pool, elevation 1,229 feet, it holds on the order of 26 million acre-feet and stretches roughly 110 miles behind Hoover Dam. It supplies water to about 25 million people across Nevada, Arizona, California, and Mexico, along with hydroelectric power.
More water is committed to users than the Colorado River reliably delivers. The 1922 Compact's allocations were set in an unusually wet period and exceed the river's long-term average flow, and Lower Basin draws plus evaporation routinely exceed what Lake Powell releases into Mead. Drought and warming since around 2000 have deepened this structural deficit.
For 2026 the river is in a Level 1 Shortage, declared when Lake Mead's projected end-of-2025 elevation fell between 1,075 and 1,050 feet. That means mandatory delivery cuts for Arizona and Nevada and reduced deliveries to Mexico. The 2007 rules behind these tiers expire at the end of 2026, and as of mid-2026 the replacement rules are still being negotiated.
Dead pool, near elevation 895 feet, is the level at which water can no longer flow through Hoover Dam to downstream users, cutting off gravity delivery to the Lower Basin and Mexico. Before that, below minimum power pool, roughly 950 feet since wide-head turbines were installed around 2016, the dam can still pass water but produces no power.
The pale band on the rock walls, the so-called bathtub ring, is a mineral crust, chiefly calcium carbonate, left where the water surface once stood. Its top marks the reservoir's former high-water lines, and the distance down to today's surface records how far the lake has dropped. With the lake near record lows in the 2020s, the ring stands well over a hundred feet tall in places.
California holds the largest Lower Basin share at 4.4 maf, Arizona 2.8 maf, and Nevada 0.3 maf, with Mexico receiving water under the 1944 treaty. Arizona's Central Arizona Project water carries a junior priority, so it absorbs the largest cuts in a shortage. Nevada's share, drawn by the Southern Nevada Water Authority for Las Vegas, uses a deep third intake that works down toward dead-pool levels.
Lake Mead hit its highest recorded level, about 1,225.85 feet, on July 24, 1983, when a large spring runoff forced Hoover Dam to open its spillways for the first time since 1941. The lake stayed relatively full through the 1980s and 1990s, then sustained drought and over-allocation beginning around 2000 pulled it down by well over a hundred feet.
As of September 5, 2026, Lake Mead is at 1,038.94 ft, a new all-time record low. Before 2026, the record low was 1,040.5 ft, set on July 28, 2022, and the lake is roughly a quarter to a third full. The Bureau of Reclamation's July 2026 24-Month Study, the monthly projection that drives shortage declarations, projected a fall to a new all-time record low within weeks, and the river is operating under a Level 1 Shortage for 2026.
Built by Daniel P. Ames, PhD — Civil & Environmental Engineering.