How hard is the water in Washington County, CO?
22.5 grains per gallon
A softener will pay its way here.
The median hardness measured in Washington County, CO is 385 mg/L as calcium carbonate, which is 22.5 gpg. That is very hard on the USGS scale. It comes from 40 samples at 14 sites between 1994 and 2023, drawn from every sampling site in the county, wells and surface water together.
How much it varies here
Half the sites came in between 20.3 and 30.3 gpg. The whole middle of that range gives the same answer, so a test of your own tap is unlikely to change it. Confidence in the county figure: high (how it is measured).
What to do next
At 22.5 gpg a softener pays its way here. Before you buy, check the quoted unit's grain capacity against the sizing table below, and ask whether it regenerates on demand, which uses less salt than a timer. Call your utility for its own report if you are on city water.
More on sizing a softener for your household.
From 9.8 to 55.1 gpg
The softest single sample on record in Washington County was 167 mg/L and the hardest 944 mg/L, a 6-fold gap. The top quarter of sites read above 30.3 gpg and the bottom quarter below 20.3 gpg.
Wells 26.6 gpg, rivers and lakes 22.5 gpg
5 groundwater samples from 2 wells put the median at 456 mg/L. 35 surface samples from 12 sites put it at 385 mg/L. In Washington County the wells come out 4.1 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 32,000-grain unit covers a week between regenerations. Expect about 491 lb of salt a year (13 bags of 40 lb, about $88), 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 $188 a year.
Sizing at 22.5 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,350 | 24,000 | 164 lb |
| 2 | 2,700 | 24,000 | 329 lb |
| 4 | 5,400 | 40,000 | 657 lb |
| 6 | 8,100 | 64,000 | 986 lb |
Washington County against the rest of Colorado
Among the 63 Colorado counties with data, Washington County is number 15 of 63 counting from the hardest. Across the whole country it is harder than 89% of counties.
Softest in Colorado: Larimer County at 0.4 gpg. Hardest: Mesa County at 143.7 gpg. Closest to Washington County: Eagle County (22.1), Logan County (22.1), Fremont County (21.7).