How hard is the water in Hidalgo County, NM?
5.8 grains per gallon
Optional: a softener helps, but plenty of homes skip it.
The median hardness measured in Hidalgo County, NM is 100 mg/L as calcium carbonate, which is 5.8 gpg. That is moderately hard on the USGS scale. It comes from 28 samples at 10 sites between 1990 and 2014, 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 1.7 and 9.3 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 5.8 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 Hidalgo 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 0.8 to 11.7 gpg
The softest single sample on record in Hidalgo County was 13 mg/L and the hardest 200 mg/L, a 15-fold gap. The top quarter of sites read above 9.3 gpg and the bottom quarter below 1.7 gpg.
Wells 5.8 gpg, rivers and lakes 8.5 gpg
28 groundwater samples from 10 wells put the median at 100 mg/L. 14 surface samples from 3 sites put it at 145.5 mg/L. In Hidalgo County the rivers and lakes come out 2.7 gpg harder. Here the surface water reads harder than the wells, which often points to streams fed by limestone springs or irrigation return flow. The two sources are close, so the county figure should hold whichever one your tap is on.
What a softener would cost to run
For a household of 3, a 24,000-grain unit covers a week between regenerations. Expect about 128 lb of salt a year (4 bags of 40 lb, about $23), 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 $123 a year.
Sizing at 5.8 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 348 | 24,000 | 42 lb |
| 2 | 696 | 24,000 | 85 lb |
| 4 | 1,392 | 24,000 | 169 lb |
| 6 | 2,088 | 24,000 | 254 lb |
Hidalgo County against the rest of New Mexico
Among the 33 New Mexico counties with data, Hidalgo County is number 28 of 33 counting from the hardest. Across the whole country it is harder than 34% of counties.
Softest in New Mexico: Rio Arriba County at 2.3 gpg. Hardest: Chaves County at 116.2 gpg. Closest to Hidalgo County: Catron County (5.1), San Miguel County (6.6), Taos County (4.9).