The Lake Mead Bathtub Ring

A white gauge of everything the lake has lost — measured daily.

• The Lake Mead "bathtub ring" is the white mineral band on the canyon walls between the lake's historic high-water line and today's surface — calcium carbonate deposited while the rock was underwater.
• As of July 23, 2026, with the lake at 1,041.38 feet against a 1,219.6-foot full pool, the ring is about 178 feet tall.
• At the July 2022 record low (1,040.58 ft) the ring reached about 179 feet — its tallest since the reservoir first filled.

Why the ring is white

Lake Mead's water carries dissolved minerals; while rock is submerged, light-colored carbonate scale builds up on it. When the level drops, the scale is exposed as a sharp white band. Its height is simple arithmetic: full pool elevation minus current elevation, so the ring grows exactly as fast as the lake falls — a visible gauge of the difference between 1,219.6 ft and today's 1,041.38 ft.

Track it

The daily number behind the ring: Lake Mead water level. Context: dead pool · shortage tiers · USBR projections.