How hard is the water in Coconino County, AZ?
14.6 grains per gallon
A softener will pay its way here.
The median hardness measured in Coconino County, AZ is 250 mg/L as calcium carbonate, which is 14.6 gpg. That is very hard on the USGS scale. It comes from 767 samples at 304 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 9.7 and 23.5 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 14.6 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. Because Coconino 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 0.4 to 163.0 gpg
The softest single sample on record in Coconino County was 6.7 mg/L and the hardest 2,790 mg/L, a 416-fold gap. The top quarter of sites read above 23.5 gpg and the bottom quarter below 9.7 gpg. So even here some sites draw water soft enough to need nothing at all.
Wells 14.6 gpg, rivers and lakes 12.9 gpg
767 groundwater samples from 304 wells put the median at 250.3 mg/L. 1,009 surface samples from 117 sites put it at 220 mg/L. In Coconino County the wells come out 1.7 gpg harder. Groundwater sits in contact with rock for years and picks up calcium and magnesium as it goes, so wells usually read harder. 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 319 lb of salt a year (8 bags of 40 lb, about $57), 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 $157 a year.
Sizing at 14.6 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 876 | 24,000 | 107 lb |
| 2 | 1,752 | 24,000 | 213 lb |
| 4 | 3,504 | 32,000 | 426 lb |
| 6 | 5,256 | 40,000 | 639 lb |
Coconino County against the rest of Arizona
Among the 15 Arizona counties with data, Coconino County is number 4 of 15 counting from the hardest. Across the whole country it is harder than 68% of counties.
Softest in Arizona: Navajo County at 9 gpg. Hardest: Yuma County at 28.7 gpg. Closest to Coconino County: Yavapai County (14.3), Maricopa County (13.8), Pinal County (12.9).