Measured, not modelled
Measured well-water hardness for Michigan, county by county: the median of laboratory hardness samples taken at real water wells, in grains per gallon and mg/L as CaCO3, with the number of wells behind every figure.
Most published hardness-by-county tables are estimates from municipal tap water. The figures below are different: they are medians of laboratory samples taken at water wells, from the public record, and every row says how many wells stand behind it. The same table qualifies every lead Hard Water Feed sells, so this page is also how you check our arithmetic — the full method is on the methodology page.
Ratings below use the Water Quality Association scale, in grains per gallon (gpg); 1 gpg is 17.118 mg/L as CaCO3.
| Rating | Range |
|---|---|
| soft | 0 – 1 gpg |
| slightly hard | 1 – 3.5 gpg |
| moderately hard | 3.5 – 7 gpg |
| hard | 7 – 10.5 gpg |
| very hard | over 10.5 gpg |
Source: Water Quality Portal (USGS & US EPA). Water Quality Portal (USGS NWIS + EPA STORET), siteType Well, 13 analytes. 2004 wells filed a hardness value; 3 had it computed from calcium + magnesium. 218 local cells, 49 counties. 4 counties dropped for straddling the softener threshold. A county appears only when at least 3 distinct wells carry a laboratory hardness result; the 34 of Michigan’s 83 counties not listed fall short of that bar or fall under the note above, and they are left out rather than guessed at.
| County | Median (gpg) | mg/L CaCO3 | Rating | Wells | Samples |
|---|---|---|---|---|---|
| Allegan | 18 | 308 | very hard | 7 | 7 |
| Antrim | 11.1 | 190 | very hard | 3 | 3 |
| Arenac | 19.3 | 330 | very hard | 15 | 15 |
| Barry | 15.5 | 265 | very hard | 24 | 24 |
| Bay | 37.9 | 649 | very hard | 29 | 29 |
| Calhoun | 19.5 | 334 | very hard | 18 | 18 |
| Clare | 14.1 | 241 | very hard | 6 | 6 |
| Clinton | 17.8 | 305 | very hard | 153 | 153 |
| Crawford | 9.1 | 156 | hard | 6 | 6 |
| Eaton | 19.9 | 341 | very hard | 87 | 87 |
| Gladwin | 20 | 342 | very hard | 17 | 17 |
| Grand Traverse | 11.3 | 193 | very hard | 36 | 36 |
| Gratiot | 22.2 | 380 | very hard | 22 | 22 |
| Huron | 16 | 274 | very hard | 67 | 67 |
| Ingham | 19 | 325 | very hard | 196 | 196 |
| Ionia | 18.7 | 320 | very hard | 27 | 27 |
| Iosco | 17.2 | 294 | very hard | 13 | 13 |
| Isabella | 25.6 | 438 | very hard | 18 | 18 |
| Jackson | 18.1 | 310 | very hard | 46 | 46 |
| Kalamazoo | 16.8 | 288 | very hard | 66 | 66 |
| Kalkaska | 10.4 | 178 | hard | 4 | 4 |
| Kent | 17.7 | 303 | very hard | 24 | 24 |
| Lapeer | 15.8 | 270 | very hard | 37 | 37 |
| Leelanau | 10.5 | 180 | very hard | 17 | 17 |
| Lenawee | 22.1 | 378 | very hard | 16 | 16 |
| Livingston | 21.1 | 361 | very hard | 62 | 62 |
| Macomb | 16.7 | 286 | very hard | 8 | 8 |
| Mason | 12.8 | 219 | very hard | 4 | 4 |
| Mecosta | 11.5 | 197 | very hard | 6 | 6 |
| Midland | 17.7 | 303 | very hard | 24 | 24 |
| Missaukee | 10 | 171 | hard | 6 | 6 |
| Monroe | 26.4 | 452 | very hard | 69 | 69 |
| Montcalm | 17.2 | 294 | very hard | 11 | 11 |
| Muskegon | 17.1 | 293 | very hard | 17 | 17 |
| Newaygo | 11.7 | 200 | very hard | 9 | 9 |
| Oakland | 16.8 | 288 | very hard | 346 | 346 |
| Oceana | 10 | 171 | hard | 7 | 7 |
| Ogemaw | 10 | 171 | hard | 9 | 9 |
| Osceola | 12.3 | 211 | very hard | 5 | 5 |
| Oscoda | 11 | 188 | very hard | 4 | 4 |
| Ottawa | 17.9 | 306 | very hard | 16 | 16 |
| Saginaw | 20.7 | 354 | very hard | 44 | 44 |
| Sanilac | 14.8 | 253 | very hard | 24 | 24 |
| Shiawassee | 17.5 | 300 | very hard | 25 | 25 |
| St. Clair | 12.9 | 221 | very hard | 25 | 25 |
| Tuscola | 12.9 | 221 | very hard | 24 | 24 |
| Washtenaw | 16.9 | 289 | very hard | 191 | 191 |
| Wayne | 30.4 | 520 | very hard | 11 | 11 |
| Wexford | 10 | 171 | hard | 8 | 8 |
Yes — the median of 346 laboratory hardness samples from 346 measured wells in Oakland County is 16.8 grains per gallon (about 288 mg/L as CaCO3), which is “very hard” on the Water Quality Association scale. This is groundwater measured at other wells in the county, not a reading from any one property.
Yes — the median of 196 laboratory hardness samples from 196 measured wells in Ingham County is 19 grains per gallon (about 325 mg/L as CaCO3), which is “very hard” on the Water Quality Association scale. This is groundwater measured at other wells in the county, not a reading from any one property.
Yes — the median of 191 laboratory hardness samples from 191 measured wells in Washtenaw County is 16.9 grains per gallon (about 289 mg/L as CaCO3), which is “very hard” on the Water Quality Association scale. This is groundwater measured at other wells in the county, not a reading from any one property.
Yes — the median of 153 laboratory hardness samples from 153 measured wells in Clinton County is 17.8 grains per gallon (about 305 mg/L as CaCO3), which is “very hard” on the Water Quality Association scale. This is groundwater measured at other wells in the county, not a reading from any one property.
Yes — the median of 87 laboratory hardness samples from 87 measured wells in Eaton County is 19.9 grains per gallon (about 341 mg/L as CaCO3), which is “very hard” on the Water Quality Association scale. This is groundwater measured at other wells in the county, not a reading from any one property.
Yes — the median of 69 laboratory hardness samples from 69 measured wells in Monroe County is 26.4 grains per gallon (about 452 mg/L as CaCO3), which is “very hard” on the Water Quality Association scale. This is groundwater measured at other wells in the county, not a reading from any one property.
Yes — the median of 67 laboratory hardness samples from 67 measured wells in Huron County is 16 grains per gallon (about 274 mg/L as CaCO3), which is “very hard” on the Water Quality Association scale. This is groundwater measured at other wells in the county, not a reading from any one property.
Yes — the median of 66 laboratory hardness samples from 66 measured wells in Kalamazoo County is 16.8 grains per gallon (about 288 mg/L as CaCO3), which is “very hard” on the Water Quality Association scale. This is groundwater measured at other wells in the county, not a reading from any one property.
Yes — the median of 62 laboratory hardness samples from 62 measured wells in Livingston County is 21.1 grains per gallon (about 361 mg/L as CaCO3), which is “very hard” on the Water Quality Association scale. This is groundwater measured at other wells in the county, not a reading from any one property.
Yes — the median of 46 laboratory hardness samples from 46 measured wells in Jackson County is 18.1 grains per gallon (about 310 mg/L as CaCO3), which is “very hard” on the Water Quality Association scale. This is groundwater measured at other wells in the county, not a reading from any one property.
The answers above cover the 10 counties with the most measured wells; the table covers every county that clears the minimum. If your county isn’t listed, the honest answer is that the public record doesn’t hold enough well samples there for us to say — not that its water is soft.
Hard Water Feed publishes a weekly feed of newly filed domestic wells in these counties, qualified against this same hardness table and sold to one water-treatment business per territory. The territory grid shows what’s open; the category guide explains the mechanism.
Built from the same data that builds the feed, and regenerated with it — figures on this page change only when the underlying public record does.