How hard is the water in La Plata County, CO?
8.4 grains per gallon
A softener is worth it here.
The median hardness measured in La Plata County, CO is 143 mg/L as calcium carbonate, which is 8.4 gpg. That is hard on the USGS scale. It comes from 57 samples at 38 sites between 1990 and 2026, drawn from groundwater wells, which is what most taps and private wells in the county draw on.
How much it varies here
Half the sites came in between 3.5 and 17 gpg. That spread crosses a decision line, so some homes here land on a different answer. A $10 test strip on your own tap settles it. Confidence in the county figure: high (how it is measured).
What to do next
At 8.4 gpg a softener is worth getting, mainly to protect the water heater and cut soap use. Get at least two quotes, ask each installer what grain capacity they are fitting, and check it against the sizing table below. Because La Plata County straddles a decision line, check your own tap with a $10 test strip before you spend anything.
More on sizing a softener for your household.
From 0.6 to 37.8 gpg
The softest single sample on record in La Plata County was 10.2 mg/L and the hardest 647 mg/L, a 63-fold gap. The top quarter of sites read above 17 gpg and the bottom quarter below 3.5 gpg. So even here some sites draw water soft enough to need nothing at all.
Wells 8.4 gpg, rivers and lakes 7.7 gpg
57 groundwater samples from 38 wells put the median at 143 mg/L. 8,064 surface samples from 228 sites put it at 132.3 mg/L. In La Plata County the wells come out 0.7 gpg harder. Groundwater sits in contact with rock for years and picks up calcium and magnesium as it goes, so wells usually read harder. The two sources are close, so the county figure should hold whichever one your tap is on.
What a softener would cost to run
For a household of 3, a 24,000-grain unit covers a week between regenerations. Expect about 182 lb of salt a year (5 bags of 40 lb, about $33), and roughly 2,346 gallons of regeneration water. Installed, most units run $1,000 to $4,500; spread over 15 years with salt, that is about $133 a year.
Sizing at 8.4 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 504 | 24,000 | 61 lb |
| 2 | 1,008 | 24,000 | 123 lb |
| 4 | 2,016 | 24,000 | 245 lb |
| 6 | 3,024 | 24,000 | 368 lb |
La Plata County against the rest of Colorado
Among the 63 Colorado counties with data, La Plata County is number 41 of 63 counting from the hardest. Across the whole country it is harder than 44% of counties.
Softest in Colorado: Larimer County at 0.4 gpg. Hardest: Mesa County at 143.7 gpg. Closest to La Plata County: Mineral County (8.2), Las Animas County (8.5), Lake County (7.7).