How hard is the water in Oakland County, MI?
18.7 grains per gallon
A softener will pay its way here.
The median hardness measured in Oakland County, MI is 320 mg/L as calcium carbonate, which is 18.7 gpg. That is very hard on the USGS scale. It comes from 175 samples at 101 sites between 1996 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 15.5 and 22.2 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 18.7 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 0.0 to 39.4 gpg
The softest single sample on record in Oakland County was 0.6 mg/L and the hardest 674 mg/L, a 1,123-fold gap. The top quarter of sites read above 22.2 gpg and the bottom quarter below 15.5 gpg. So even here some sites draw water soft enough to need nothing at all.
Wells 18.7 gpg, rivers and lakes 13.4 gpg
175 groundwater samples from 101 wells put the median at 320 mg/L. 229 surface samples from 51 sites put it at 230 mg/L. In Oakland County the wells come out 5.3 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 24,000-grain unit covers a week between regenerations. Expect about 408 lb of salt a year (11 bags of 40 lb, about $73), 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 $173 a year.
Sizing at 18.7 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,122 | 24,000 | 137 lb |
| 2 | 2,244 | 24,000 | 273 lb |
| 4 | 4,488 | 32,000 | 546 lb |
| 6 | 6,732 | 48,000 | 819 lb |
Oakland County against the rest of Michigan
Among the 82 Michigan counties with data, Oakland County is number 11 of 82 counting from the hardest. Across the whole country it is harder than 81% of counties.
Softest in Michigan: Luce County at 1.9 gpg. Hardest: Wayne County at 47.4 gpg. Closest to Oakland County: Macomb County (18.4), Shiawassee County (18.3), Dickinson County (18).