How hard is the water in Navajo County, AZ?
9 grains per gallon
A softener is worth it here.
The median hardness measured in Navajo County, AZ is 154 mg/L as calcium carbonate, which is 9 gpg. That is hard on the USGS scale. It comes from 478 samples at 198 sites between 1990 and 2023, 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 3.9 and 16.1 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 9 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 Navajo 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 0.0 to 217.3 gpg
The softest single sample on record in Navajo County was 0.8 mg/L and the hardest 3,720 mg/L, a 4,650-fold gap. The top quarter of sites read above 16.1 gpg and the bottom quarter below 3.9 gpg. So even here some sites draw water soft enough to need nothing at all.
Wells 9 gpg, rivers and lakes 11.3 gpg
478 groundwater samples from 198 wells put the median at 153.5 mg/L. 206 surface samples from 53 sites put it at 194 mg/L. In Navajo County the rivers and lakes come out 2.3 gpg harder. Here the surface water reads harder than the wells, which often points to streams fed by limestone springs or irrigation return flow. 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 196 lb of salt a year (5 bags of 40 lb, about $35), 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 $135 a year.
Sizing at 9 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 540 | 24,000 | 66 lb |
| 2 | 1,080 | 24,000 | 131 lb |
| 4 | 2,160 | 24,000 | 263 lb |
| 6 | 3,240 | 24,000 | 394 lb |
Navajo County against the rest of Arizona
Among the 15 Arizona counties with data, Navajo County is the softest. Across the whole country it is harder than 47% of counties.
Hardest: Yuma County at 28.7 gpg. Closest to Navajo County: Apache County (9.4), La Paz County (9.6), Cochise County (9.8).