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Water Hardness in Wyoming

Across 6 measured cities — with 62 more covered by labeled county-level estimates — Wyoming's median tap water hardness is 49.3 mg/L (2.9 gpg): soft on the USGS scale. Below: every covered city, the state's hardest and softest water, and the geology that explains it.

Data updated July 6, 2026. Sources: utility-reported water quality data and USGS/EPA Water Quality Portal samples.

State Median
49.3
mg/L (2.9 gpg), measured cities
Measured Range
27.1-327.0
mg/L across measured cities
Measured Cities
6
utility-reported or computed values
County Estimates
62
91% of covered cities

Wyoming Cities by Hardness Category

Measured cities only — labeled county estimates never enter the category counts or the median.

CategoryRangeMeasured citiesShare
Soft0-60 mg/L466.7%
Moderately hard60-120 mg/L00.0%
Hard120-180 mg/L116.7%
Very hard>180 mg/L116.7%

Hardest and Softest Water in Wyoming

Measured values only; labeled county estimates and values under active dispute never rank.

Hardest water in Wyoming

  1. Casper — 327.0 mg/L (19.1 gpg), very hard
  2. Jackson — 163.0 mg/L (9.5 gpg), hard
  3. Cheyenne — 49.3 mg/L (2.9 gpg), soft
  4. Fox Farm-College — 49.3 mg/L (2.9 gpg), soft
  5. South Greeley — 49.3 mg/L (2.9 gpg), soft

Softest water in Wyoming

  1. Sheridan — 27.1 mg/L (1.6 gpg), soft
  2. Cheyenne — 49.3 mg/L (2.9 gpg), soft
  3. Fox Farm-College — 49.3 mg/L (2.9 gpg), soft
  4. South Greeley — 49.3 mg/L (2.9 gpg), soft
  5. Jackson — 163.0 mg/L (9.5 gpg), hard

Every Covered City in Wyoming

All 68 covered Wyoming cities, sorted by population served. "County estimate" rows are labeled context values from USGS/EPA Water Quality Portal county sampling — they never enter the median above. City names link to each city's full water quality page.

CityHardness (mg/L)gpgCategoryData
Cheyenne49.32.9SoftUtility-reported
Casper327.019.1Very hardUtility-reported
South Greeley49.32.9SoftUtility-reported
Fox Farm-College49.32.9SoftUtility-reported
Rock Springs209.612.3Very hardCounty estimate
Sheridan27.11.6SoftUtility-reported
Cody39.22.3SoftCounty estimate
Jackson163.09.5HardUtility-reported
Green River209.612.3Very hardCounty estimate
Evanston190.911.2Very hardCounty estimate
Riverton6.00.3SoftCounty estimate
Mills166.09.7HardCounty estimate
Lander6.00.3SoftCounty estimate
Powell39.22.3SoftCounty estimate
Torrington195.011.4Very hardCounty estimate
Worland251.014.7Very hardCounty estimate
Newcastle342.020.0Very hardCounty estimate
Buffalo510.029.8Very hardCounty estimate
Thermopolis4.00.2SoftCounty estimate
Alcova166.09.7HardCounty estimate
Lyman81.34.8Moderately hardCounty estimate
Wheatland243.014.2Very hardCounty estimate
Fort Washakie6.00.3SoftCounty estimate
Greybull282.016.5Very hardCounty estimate
Kemmerer198.511.6Very hardCounty estimate
Evansville166.09.7HardCounty estimate
Wright926.054.1Very hardCounty estimate
Lovell282.016.5Very hardCounty estimate
Basin282.016.5Very hardCounty estimate
Little America209.612.3Very hardCounty estimate
Afton198.511.6Very hardCounty estimate
Pinedale7.40.4SoftCounty estimate
Dubois6.00.3SoftCounty estimate
Saratoga226.013.2Very hardCounty estimate
Lusk687.040.2Very hardCounty estimate
Alpine198.511.6Very hardCounty estimate
Pavillion6.00.3SoftCounty estimate
Sundance846.049.5Very hardCounty estimate
Mountain View81.34.8Moderately hardCounty estimate
Guernsey243.014.2Very hardCounty estimate
Upton342.020.0Very hardCounty estimate
Burns153.08.9HardCounty estimate
Moorcroft846.049.5Very hardCounty estimate
Ranchester418.024.4Very hardCounty estimate
Shoshoni6.00.3SoftCounty estimate
Byron282.016.5Very hardCounty estimate
Cokeville198.511.6Very hardCounty estimate
Lingle195.011.4Very hardCounty estimate
Hudson6.00.3SoftCounty estimate
Burlington282.016.5Very hardCounty estimate
La Barge198.511.6Very hardCounty estimate
Meeteetse39.22.3SoftCounty estimate
Gillette926.054.1Very hardCounty estimate
Glendo243.014.2Very hardCounty estimate
Fort Laramie195.011.4Very hardCounty estimate
Chugwater243.014.2Very hardCounty estimate
Deaver282.016.5Very hardCounty estimate
Clearmont418.024.4Very hardCounty estimate
Granger209.612.3Very hardCounty estimate
Yoder195.011.4Very hardCounty estimate
Shell282.016.5Very hardCounty estimate
Manderson282.016.5Very hardCounty estimate
Wilson79.64.7Moderately hardCounty estimate
Hyattville282.016.5Very hardCounty estimate
Opal198.511.6Very hardCounty estimate
Hartville243.014.2Very hardCounty estimate
Kirby4.00.2SoftCounty estimate
Grover198.511.6Very hardCounty estimate

Above 120 mg/L (7 gpg), scale is usually worth treating — see our water softener guide, or size a system with the hardness calculator & converter.

The Geology Behind Wyoming's Water Hardness

Wyoming sits in the Mountain West basins and desert Southwest region.

Mountain snowmelt starts out soft, but across the interior West it drains into closed basins floored with carbonate and evaporite sediments, and the arid climate evaporates water faster than rain can dilute it. Rivers like the Colorado accumulate dissolved calcium and magnesium along their whole length, so the USGS maps most basin-and-range and desert-Southwest supplies as hard to very hard. Towns high in the mountains that capture snowmelt directly are the region's soft-water exceptions.

Source: USGS Water Science School - Hardness of Water

Wyoming Water Hardness FAQ

Does Wyoming have hard water?

On the whole, no — Wyoming's statewide median sits below the hard threshold, though some cities run harder. The median is 49.3 mg/L (2.9 gpg) — soft on the USGS scale, where anything above 120 mg/L (7 gpg) counts as hard. 2 of Wyoming's 6 measured cities fall in the hard or very hard bands (33%), so check your own city rather than the state average.

How hard is tap water in Wyoming?

Across the 6 Wyoming cities with measured values in our index, the median hardness is 49.3 mg/L (2.9 gpg) — soft on the USGS scale. Individual cities range from 27.1 to 327.0 mg/L, so check your own city rather than assuming the state number.

Which city in Wyoming has the hardest water?

Casper has the hardest measured tap water in our Wyoming index at 327.0 mg/L (19.1 gpg) — very hard on the USGS scale. Rankings use measured utility values only; labeled county estimates and values under active dispute are excluded.

Do I need a water softener in Wyoming?

2 of Wyoming's 6 measured cities (33%) fall in the hard or very hard bands — above 120 mg/L (7 gpg), the level where most water treatment professionals suggest considering an ion-exchange softener. Hardness varies utility to utility, so look up your own city's value before sizing equipment.

How do I find my city's exact water hardness?

Enter your ZIP code in our free lookup at tapwaterdata.com/zip to see the value we hold for your Wyoming city from utility-reported water quality data, check your water utility's annual Consumer Confidence Report (CCR), or use a home test-strip kit.

← Water hardness across the USInteractive hardness mapCalculator & converterFree ZIP-code hardness lookupData & methodology

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