How hard is the water in Gilpin County, CO?
6.3 grains per gallon
Optional: a softener helps, but plenty of homes skip it.
The median hardness measured in Gilpin County, CO is 107 mg/L as calcium carbonate, which is 6.3 gpg. That is moderately hard on the USGS scale. It comes from 860 samples at 97 sites between 1990 and 2022, drawn from every sampling site in the county, wells and surface water together.
How much it varies here
Half the sites came in between 2.4 and 13.5 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 6.3 gpg this is your call. Look for white film on glasses and crust on the shower head: if you see little of either, you can live without one. If you do want one, a 24,000-grain unit is enough, so ask for that size rather than a bigger one. Because Gilpin County straddles a decision line, check your own tap with a $10 test strip before you spend anything.
More on when a softener is not worth it.
From 0.5 to 93.5 gpg
The softest single sample on record in Gilpin County was 8 mg/L and the hardest 1,601.1 mg/L, a 200-fold gap. The top quarter of sites read above 13.5 gpg and the bottom quarter below 2.4 gpg.
Wells 8.9 gpg, rivers and lakes 5.3 gpg
3 groundwater samples from 3 wells put the median at 153 mg/L. 795 surface samples from 86 sites put it at 90 mg/L. In Gilpin County the wells come out 3.6 gpg harder. Groundwater sits in contact with rock for years and picks up calcium and magnesium as it goes, so wells usually read harder. A utility here that draws from the river can deliver noticeably different water from a private well next door.
What a softener would cost to run
For a household of 3, a 24,000-grain unit covers a week between regenerations. Expect about 137 lb of salt a year (4 bags of 40 lb, about $25), 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 $125 a year.
Sizing at 6.3 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 378 | 24,000 | 46 lb |
| 2 | 756 | 24,000 | 92 lb |
| 4 | 1,512 | 24,000 | 184 lb |
| 6 | 2,268 | 24,000 | 276 lb |
Gilpin County against the rest of Colorado
Among the 63 Colorado counties with data, Gilpin County is number 51 of 63 counting from the hardest. Across the whole country it is harder than 36% of counties.
Softest in Colorado: Larimer County at 0.4 gpg. Hardest: Mesa County at 143.7 gpg. Closest to Gilpin County: Custer County (6.3), Douglas County (6.5), Archuleta County (5.8).