How hard is the water in La Paz County, AZ?
9.6 grains per gallon
A softener is worth it here.
The median hardness measured in La Paz County, AZ is 165 mg/L as calcium carbonate, which is 9.6 gpg. That is hard on the USGS scale. It comes from 571 samples at 268 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 5.7 and 14.6 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: high (how it is measured).
What to do next
At 9.6 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 La Paz 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 0.2 to 130.3 gpg
The softest single sample on record in La Paz County was 3.9 mg/L and the hardest 2,230 mg/L, a 572-fold gap. The top quarter of sites read above 14.6 gpg and the bottom quarter below 5.7 gpg. So even here some sites draw water soft enough to need nothing at all.
Wells 9.6 gpg, rivers and lakes 15.9 gpg
571 groundwater samples from 268 wells put the median at 164.5 mg/L. 131 surface samples from 11 sites put it at 272.5 mg/L. In La Paz 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 210 lb of salt a year (6 bags of 40 lb, about $38), 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 $138 a year.
Sizing at 9.6 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 576 | 24,000 | 70 lb |
| 2 | 1,152 | 24,000 | 140 lb |
| 4 | 2,304 | 24,000 | 280 lb |
| 6 | 3,456 | 32,000 | 420 lb |
La Paz County against the rest of Arizona
Among the 15 Arizona counties with data, La Paz County is number 13 of 15 counting from the hardest. Across the whole country it is harder than 50% of counties.
Softest in Arizona: Navajo County at 9 gpg. Hardest: Yuma County at 28.7 gpg. Closest to La Paz County: Apache County (9.4), Cochise County (9.8), Graham County (9.9).