How hard is the water in Grant County, NM?
7.8 grains per gallon
A softener is worth it here.
The median hardness measured in Grant County, NM is 133 mg/L as calcium carbonate, which is 7.8 gpg. That is hard on the USGS scale. It comes from 382 samples at 40 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 4.5 and 11.7 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 7.8 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 Grant 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 1.8 to 86.5 gpg
The softest single sample on record in Grant County was 30 mg/L and the hardest 1,480 mg/L, a 49-fold gap. The top quarter of sites read above 11.7 gpg and the bottom quarter below 4.5 gpg. So even here some sites draw water soft enough to need nothing at all.
Wells 48.5 gpg, rivers and lakes 7 gpg
5 groundwater samples from 3 wells put the median at 830 mg/L. 376 surface samples from 36 sites put it at 119 mg/L. In Grant County the wells come out 41.5 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 169 lb of salt a year (5 bags of 40 lb, about $30), 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 $130 a year.
Sizing at 7.8 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 468 | 24,000 | 57 lb |
| 2 | 936 | 24,000 | 114 lb |
| 4 | 1,872 | 24,000 | 228 lb |
| 6 | 2,808 | 24,000 | 342 lb |
Grant County against the rest of New Mexico
Among the 33 New Mexico counties with data, Grant County is number 25 of 33 counting from the hardest. Across the whole country it is harder than 42% of counties.
Softest in New Mexico: Rio Arriba County at 2.3 gpg. Hardest: Chaves County at 116.2 gpg. Closest to Grant County: Socorro County (7.9), McKinley County (7), Valencia County (8.9).