Water Hardness Atlas ZIP / postcode

Well water hardness in Park County, Wyoming

13.1 gpg very hard

Private wells in Park County typically give very hard water: the median well sampled by the U.S. Geological Survey has 13.1 gpg (225 mg/L as CaCO₃).

<6060–120120–180>180 mg/L

Wells differ a lot, even next door: one in ten sampled wells had less than 20 mg/L and one in ten more than 558 mg/L. The figure comes from 64 wells and 86 samples taken between 1980 and 2007 (half of them by 1987).

Most samples are older than ten years. Groundwater hardness comes from the rock the well is drilled into and changes slowly, but your own well can be quite different, so treat this as a regional indication and test your water.

What this hardness means for a well household

How to test your well in Wyoming

Hardness is only one part of a well test. Federal health agencies advise every private well owner to test regularly:

Use a certified laboratory: Wyoming DEQ, Know Your Well (list of laboratories for homeowners).

Testing is your own responsibility: no state agency samples existing private wells routinely.

What a test costs (Teton County Water Lab (bacteria only))

Drinking water bacteria test$25

Prices as printed by the lab (2026-10-29); check the current fee before you send a sample. Teton County Water Lab (bacteria only)

If no local lab suits you, mail-in kits from certified labs test a wider panel at home; they cost more than a state or county lab.

Treating hard well water

At this hardness an ion-exchange softener sized for your household is the usual answer. Test iron, manganese and pH first: well water often needs an iron filter or a pH correction in front of the softener.

Nearby counties

Carbon County, MT15.1 gpgBig Horn County15.4 gpgHot Springs County14.2 gpgWashakie County11.9 gpgStillwater County, MT9.3 gpgSweet Grass County, MT9.3 gpg

FAQ

How hard is well water in Park County, Wyoming?

The median well sampled by the USGS in Park County has 13.1 gpg (225 mg/L as CaCO₃), which is very hard. One in ten wells had less than 20 mg/L and one in ten more than 558 mg/L.

Is my own well the same?

Not necessarily. Hardness depends on the rock layer your well draws from and on its depth, so neighbouring wells can differ by a factor of two or more. Only a test of your own water tells you.

How often should I test my well in Wyoming?

Every year for coliform bacteria, nitrate, total dissolved solids and pH (EPA and CDC advice), and after floods, repairs or a change in taste or smell. Hardness, iron and manganese once, and again before you buy a softener.

Do I need a water softener for my well?

Yes, unless you are only passing through: scale damages appliances within a few years.

Where does this figure come from?

From 86 samples of 64 wells measured by the U.S. Geological Survey between 1980 and 2007, retrieved from the Water Quality Portal. We publish a county only when at least 10 wells were sampled.

Source and method

Computed by Water Hardness Atlas from USGS National Water Information System samples (characteristic "Hardness, Ca, Mg", sites of type well, samples since 1980), retrieved 2026-10-29 through the Water Quality Portal. For each well we take the median of its samples, then the median of all wells in the county; wells above 1,000 mg/L (oil, gas or mine brines) are left out. USGS data are in the U.S. public domain. Water Quality Portal query

Well water hardness in Wyoming →