How hard is the water in Washtenaw County, MI?
19.7 grains per gallon
A softener will pay its way here.
The median hardness measured in Washtenaw County, MI is 337 mg/L as calcium carbonate, which is 19.7 gpg. That is very hard on the USGS scale. It comes from 46 samples at 26 sites between 1990 and 2016, 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 16.3 and 24.1 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 19.7 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 0.1 to 286.2 gpg
The softest single sample on record in Washtenaw County was 1.2 mg/L and the hardest 4,900 mg/L, a 4,083-fold gap. The top quarter of sites read above 24.1 gpg and the bottom quarter below 16.3 gpg. So even here some sites draw water soft enough to need nothing at all.
Wells 19.7 gpg, rivers and lakes 11.4 gpg
46 groundwater samples from 26 wells put the median at 337.3 mg/L. 61 surface samples from 20 sites put it at 195 mg/L. In Washtenaw County the wells come out 8.3 gpg harder. Groundwater sits in contact with rock for years and picks up calcium and magnesium as it goes, so wells usually read harder. A utility here that draws from the river can deliver noticeably different water from a private well next door.
What a softener would cost to run
For a household of 3, a 32,000-grain unit covers a week between regenerations. Expect about 430 lb of salt a year (11 bags of 40 lb, about $77), 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 $177 a year.
Sizing at 19.7 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,182 | 24,000 | 144 lb |
| 2 | 2,364 | 24,000 | 288 lb |
| 4 | 4,728 | 40,000 | 575 lb |
| 6 | 7,092 | 64,000 | 863 lb |
Washtenaw County against the rest of Michigan
Among the 82 Michigan counties with data, Washtenaw County is number 10 of 82 counting from the hardest. Across the whole country it is harder than 83% of counties.
Softest in Michigan: Luce County at 1.9 gpg. Hardest: Wayne County at 47.4 gpg. Closest to Washtenaw County: Hillsdale County (20.5), Oakland County (18.7), Branch County (20.8).