How hard is the water in Union County, NM?
26.4 grains per gallon
A softener will pay its way here.
The median hardness measured in Union County, NM is 451 mg/L as calcium carbonate, which is 26.4 gpg. That is very hard on the USGS scale. It comes from 133 samples at 14 sites between 1999 and 2020, drawn from every sampling site in the county, wells and surface water together.
How much it varies here
Half the sites came in between 16.3 and 32.7 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 26.4 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 7.2 to 41.5 gpg
The softest single sample on record in Union County was 124 mg/L and the hardest 710 mg/L, a 6-fold gap. The top quarter of sites read above 32.7 gpg and the bottom quarter below 16.3 gpg.
Wells 12.4 gpg, rivers and lakes 29.1 gpg
9 groundwater samples from 3 wells put the median at 212 mg/L. 124 surface samples from 11 sites put it at 497.5 mg/L. In Union County the rivers and lakes come out 16.7 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 40,000-grain unit covers a week between regenerations. Expect about 576 lb of salt a year (15 bags of 40 lb, about $104), 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 $204 a year.
Sizing at 26.4 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,584 | 24,000 | 193 lb |
| 2 | 3,168 | 24,000 | 385 lb |
| 4 | 6,336 | 48,000 | 771 lb |
| 6 | 9,504 | 80,000 | 1,156 lb |
Union County against the rest of New Mexico
Among the 33 New Mexico counties with data, Union County is number 8 of 33 counting from the hardest. Across the whole country it is harder than 93% of counties.
Softest in New Mexico: Rio Arriba County at 2.3 gpg. Hardest: Chaves County at 116.2 gpg. Closest to Union County: Eddy County (27.1), Sierra County (27.6), Otero County (31.3).