Cheyenne Water Hardness & Quality Report (2026)

The Cheyenne Board of Public Utilities (BOPU) supplies drinking water to approximately 65,000 residents in Laramie County, Wyoming. Primary sources include surface water drawn from the Douglas Creek Watershed in the Medicine Bow Mountains, stored in Rob Roy, Granite, and Crystal Reservoirs, blended with approximately 15% groundwater from High Plains wells west of the city. Replacement water is sourced from the Little Snake River Watershed west of the Continental Divide to offset Douglas Creek diversions, with treatment facilities managing filtration from both reservoirs and wells.

The Douglas Creek Watershed spans 75 miles west in the Medicine Bow Mountains (Snowy Range), feeding the North Platte River system. Water contacts Precambrian and younger sedimentary rock formations during transit, absorbing calcium, magnesium, iron, and silica. High Plains aquifers west of the city are unconfined and susceptible to mineral enrichment from local geological pickup, yielding a harder character compared to the softer reservoir supply. This contrasting blend produces moderately mineralised water, with USGS data noting elevated dissolved solids from these formations.

As generally soft to moderately hard water, Cheyenne's supply causes minimal scaling on fixtures, glasses, and dishes, though well-heavy blends can leave spots or chalky residues. Water heaters, pipes, showerheads, and faucets see moderate buildup over time, potentially reducing efficiency or flow in older steel systems. Regular vinegar soaks for removable fixtures help; a water softener is optional for well-heavy periods but not essential for average use. Turbidity compliance is excellent — 100% of samples ≤0.062 NTU — with no violations noted in the Consumer Confidence Report.