Casper Water Hardness & Quality Report (2026)

Casper, Wyoming, the Natrona County seat on the North Platte River — Wyoming's second-largest city, a major oil, gas, and ranching hub, and the historic gateway of the Oregon, California, and Mormon pioneer trails — draws its municipal water supply from the North Platte River (Alcova Reservoir) via the City of Casper Utility Division, treating high-altitude Wyoming river water for Casper. Water hardness in Casper measures 62 mg/L — classified as moderately soft.

Casper's moderately soft supply reflects the North Platte River's Wind River Range and Rocky Mountain headwater geology. The North Platte River above Alcova Reservoir (near Casper) drains: the Wind River Range — Precambrian Archean Wyomingite Group (Wind River Gneiss and Hailey Gold Belt granite — the oldest crystalline basement in Wyoming, calcium-poor Archean gneiss and granite) — as the primary recharge; the Paleozoic Bighorn Dolomite and Madison Limestone in the Wind River foothills (some calcareous contribution); and the Triassic–Jurassic red bed formations of central Wyoming (Chugwater and Morrison Formations — limited calcareous contribution at high elevation). The dominant Wind River Range Precambrian crystalline source produces the moderate 62 mg/L soft supply.

With hardness at 62 mg/L, Casper residents enjoy moderately soft water. City of Casper Utility Division consistently delivers water meeting all Wyoming DEQ and EPA Safe Drinking Water Act requirements.