How hard is the water in Weld County, CO?
31.1 grains per gallon
A softener will pay its way here.
The median hardness measured in Weld County, CO is 532 mg/L as calcium carbonate, which is 31.1 gpg. That is very hard on the USGS scale. It comes from 237 samples at 76 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 25.6 and 41.5 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 31.1 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 0.3 to 245.3 gpg
The softest single sample on record in Weld County was 4.5 mg/L and the hardest 4,200 mg/L, a 933-fold gap. The top quarter of sites read above 41.5 gpg and the bottom quarter below 25.6 gpg. So even here some sites draw water soft enough to need nothing at all.
Wells 31.1 gpg, rivers and lakes 23.4 gpg
237 groundwater samples from 76 wells put the median at 531.8 mg/L. 3,987 surface samples from 156 sites put it at 400 mg/L. In Weld County the wells come out 7.7 gpg harder. Groundwater sits in contact with rock for years and picks up calcium and magnesium as it goes, so wells usually read harder. 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 40,000-grain unit covers a week between regenerations. Expect about 678 lb of salt a year (17 bags of 40 lb, about $122), 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 $222 a year.
Sizing at 31.1 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,866 | 24,000 | 227 lb |
| 2 | 3,732 | 32,000 | 454 lb |
| 4 | 7,464 | 64,000 | 908 lb |
| 6 | 11,196 | 80,000 | 1,362 lb |
Weld County against the rest of Colorado
Among the 63 Colorado counties with data, Weld County is number 9 of 63 counting from the hardest. Across the whole country it is harder than 95% of counties.
Softest in Colorado: Larimer County at 0.4 gpg. Hardest: Mesa County at 143.7 gpg. Closest to Weld County: Pueblo County (28), Garfield County (26.6), Denver County (24.2).