Measured, not modelled
Measured well-water hardness for Florida, 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. 2805 wells filed a hardness value; 1636 had it computed from calcium + magnesium. 404 local cells, 12 counties. 12 counties dropped for straddling the softener threshold. A county appears only when at least 3 distinct wells carry a laboratory hardness result; the 55 of Florida’s 67 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 |
|---|---|---|---|---|---|
| Alachua | 11.1 | 190 | very hard | 123 | 123 |
| Brevard | 26.5 | 454 | very hard | 61 | 61 |
| Charlotte | 24.7 | 423 | very hard | 121 | 121 |
| Desoto | 21.5 | 368 | very hard | 198 | 198 |
| Flagler | 33.1 | 567 | very hard | 36 | 36 |
| Indian River | 19.2 | 329 | very hard | 39 | 39 |
| Lee | 21 | 359 | very hard | 378 | 378 |
| Levy | 13.5 | 231 | very hard | 191 | 191 |
| Manatee | 29.8 | 510 | very hard | 324 | 324 |
| Sarasota | 30.8 | 527 | very hard | 778 | 778 |
| St. Johns | 22.2 | 380 | very hard | 68 | 68 |
| Sumter | 11.8 | 202 | very hard | 75 | 75 |
Yes — the median of 778 laboratory hardness samples from 778 measured wells in Sarasota County is 30.8 grains per gallon (about 527 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 378 laboratory hardness samples from 378 measured wells in Lee County is 21 grains per gallon (about 359 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 324 laboratory hardness samples from 324 measured wells in Manatee County is 29.8 grains per gallon (about 510 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 198 laboratory hardness samples from 198 measured wells in Desoto County is 21.5 grains per gallon (about 368 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 Levy County is 13.5 grains per gallon (about 231 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 123 laboratory hardness samples from 123 measured wells in Alachua County is 11.1 grains per gallon (about 190 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 121 laboratory hardness samples from 121 measured wells in Charlotte County is 24.7 grains per gallon (about 423 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 75 laboratory hardness samples from 75 measured wells in Sumter County is 11.8 grains per gallon (about 202 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 68 laboratory hardness samples from 68 measured wells in St. Johns County is 22.2 grains per gallon (about 380 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 61 laboratory hardness samples from 61 measured wells in Brevard County is 26.5 grains per gallon (about 454 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.
Selling water treatment in Florida? The new wells behind these figures are sold by territory — well water leads in Florida.
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.