How hard is the water in McKinley County, NM?
7 grains per gallon
Optional: a softener helps, but plenty of homes skip it.
The median hardness measured in McKinley County, NM is 119 mg/L as calcium carbonate, which is 7 gpg. That is moderately hard on the USGS scale. It comes from 24 samples at 23 sites between 1990 and 2021, 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 1.2 and 19.6 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: medium (how it is measured).
What to do next
At 7 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 McKinley 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 0.2 to 105.1 gpg
The softest single sample on record in McKinley County was 3.7 mg/L and the hardest 1,800 mg/L, a 486-fold gap. The top quarter of sites read above 19.6 gpg and the bottom quarter below 1.2 gpg.
Wells 7 gpg, rivers and lakes 13.3 gpg
24 groundwater samples from 23 wells put the median at 119 mg/L. 106 surface samples from 24 sites put it at 227.5 mg/L. In McKinley County the rivers and lakes come out 6.3 gpg harder. Here the surface water reads harder than the wells, which often points to streams fed by limestone springs or irrigation return flow. A utility here that draws from the aquifer 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 152 lb of salt a year (4 bags of 40 lb, about $27), 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 $127 a year.
Sizing at 7 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 420 | 24,000 | 51 lb |
| 2 | 840 | 24,000 | 102 lb |
| 4 | 1,680 | 24,000 | 204 lb |
| 6 | 2,520 | 24,000 | 307 lb |
McKinley County against the rest of New Mexico
Among the 33 New Mexico counties with data, McKinley County is number 26 of 33 counting from the hardest. Across the whole country it is harder than 38% of counties.
Softest in New Mexico: Rio Arriba County at 2.3 gpg. Hardest: Chaves County at 116.2 gpg. Closest to McKinley County: San Miguel County (6.6), Grant County (7.8), Socorro County (7.9).