Water hardness in Florida
Florida has a median ambient water hardness of 160 mg/L, which is 9.3 grains per gallon and classes as hard. That is the middle of 152,658 samples across 67 counties.
This is ambient water, not tap water. These figures come from samples taken from wells, streams and springs by USGS, EPA and state agencies. Municipal utilities treat, blend and sometimes soften water before it reaches a tap, so a city supply can be considerably softer than the ground beneath it. Treat this as a good guide for a private well and an approximate one for city water. Your utility's annual water quality report gives the real number for a municipal tap, and a test strip gives it for yours.
Every monitored county in Florida
Ranked hardest first. The middle 50% column shows how much the samples within a county vary, which matters more than the median where a county spans two geologies.
| County | mg/L | gpg | Class | Middle 50% | Samples |
|---|---|---|---|---|---|
| Nassau County | 567 | 33.1 | Very hard | 89 to 3,850 | 636 |
| Monroe County | 495 | 28.9 | Very hard | 170 to 4,400 | 408 |
| Charlotte County | 409 | 23.9 | Very hard | 247 to 610 | 284 |
| Sarasota County | 390 | 22.8 | Very hard | 200 to 620 | 2,498 |
| Duval County | 331 | 19.3 | Very hard | 180 to 1,665 | 6,162 |
| Collier County | 320 | 18.7 | Very hard | 194 to 2,626 | 6,270 |
| St. Lucie County | 311 | 18.2 | Very hard | 166 to 420 | 878 |
| Lee County | 296 | 17.3 | Very hard | 220 to 400 | 12,474 |
| Pinellas County | 272 | 15.9 | Very hard | 150 to 443 | 2,460 |
| Broward County | 253 | 14.8 | Very hard | 217 to 300 | 3,728 |
| Hendry County | 250 | 14.6 | Very hard | 193 to 340 | 378 |
| Miami-Dade County | 230 | 13.4 | Very hard | 203 to 260 | 7,512 |
| St. Johns County | 222 | 13 | Very hard | 142 to 683 | 4,093 |
| Levy County | 210 | 12.3 | Very hard | 130 to 280 | 659 |
| Lafayette County | 200 | 11.7 | Very hard | 161 to 238 | 268 |
| Palm Beach County | 200 | 11.7 | Very hard | 158 to 290 | 6,847 |
| Martin County | 195 | 11.4 | Very hard | 140 to 265 | 1,026 |
| Gilchrist County | 190 | 11.1 | Very hard | 150 to 230 | 279 |
| Brevard County | 185 | 10.8 | Very hard | 109 to 302 | 9,787 |
| Putnam County | 183 | 10.7 | Very hard | 132 to 231 | 5,578 |
| Indian River County | 178 | 10.4 | Hard | 71 to 243 | 6,684 |
| Dixie County | 169 | 9.9 | Hard | 101 to 200 | 137 |
| Volusia County | 169 | 9.9 | Hard | 61 to 259 | 3,769 |
| Hillsborough County | 150 | 8.8 | Hard | 83 to 200 | 5,801 |
| Taylor County | 150 | 8.8 | Hard | 76 to 209 | 551 |
| Manatee County | 149 | 8.7 | Hard | 46 to 340 | 1,165 |
| Suwannee County | 148 | 8.6 | Hard | 85 to 184 | 939 |
| Citrus County | 144 | 8.4 | Hard | 90 to 260 | 632 |
| DeSoto County | 140 | 8.2 | Hard | 85 to 207 | 1,037 |
| Hernando County | 140 | 8.2 | Hard | 82 to 168 | 649 |
| Sumter County | 140 | 8.2 | Hard | 95 to 180 | 347 |
| Lake County | 136 | 7.9 | Hard | 110 to 163 | 5,435 |
| Glades County | 132 | 7.7 | Hard | 78 to 183 | 1,077 |
| Marion County | 132 | 7.7 | Hard | 71 to 200 | 3,114 |
| Hardee County | 111 | 6.5 | Moderately hard | 61 to 180 | 374 |
| Seminole County | 111 | 6.5 | Moderately hard | 75 to 161 | 3,955 |
| Pasco County | 110 | 6.4 | Moderately hard | 47 to 176 | 1,495 |
| Calhoun County | 89 | 5.2 | Moderately hard | 72 to 100 | 326 |
| Flagler County | 87 | 5.1 | Moderately hard | 47 to 182 | 971 |
| Columbia County | 83 | 4.8 | Moderately hard | 18 to 167 | 598 |
| Hamilton County | 74 | 4.3 | Moderately hard | 22 to 157 | 470 |
| Madison County | 70 | 4.1 | Moderately hard | 21 to 139 | 270 |
| Polk County | 70 | 4.1 | Moderately hard | 48 to 92 | 3,768 |
| Orange County | 68 | 4 | Moderately hard | 51 to 116 | 14,257 |
| Jefferson County | 65 | 3.8 | Moderately hard | 11 to 157 | 116 |
| Okeechobee County | 61 | 3.6 | Moderately hard | 44 to 130 | 871 |
| Wakulla County | 57 | 3.3 | Soft | 7 to 143 | 1,002 |
| Jackson County | 54 | 3.2 | Soft | 40 to 112 | 475 |
| Osceola County | 52 | 3 | Soft | 39 to 68 | 2,852 |
| Clay County | 50 | 2.9 | Soft | 21 to 159 | 3,863 |
| Gulf County | 47 | 2.7 | Soft | 33 to 65 | 77 |
| Franklin County | 46 | 2.7 | Soft | 38 to 54 | 318 |
| Alachua County | 44 | 2.6 | Soft | 30 to 95 | 4,052 |
| Bay County | 44 | 2.6 | Soft | 28 to 53 | 457 |
| Highlands County | 34 | 2 | Soft | 24 to 51 | 681 |
| Holmes County | 31 | 1.8 | Soft | 22 to 46 | 248 |
| Gadsden County | 30 | 1.8 | Soft | 17 to 43 | 732 |
| Leon County | 29 | 1.7 | Soft | 11 to 61 | 2,083 |
| Washington County | 28 | 1.6 | Soft | 4 to 56 | 196 |
| Union County | 20 | 1.2 | Soft | 14 to 36 | 189 |
| Okaloosa County | 19 | 1.1 | Soft | 5 to 37 | 726 |
| Walton County | 18 | 1.1 | Soft | 6 to 52 | 525 |
| Bradford County | 17 | 1 | Soft | 8 to 42 | 247 |
| Santa Rosa County | 17 | 1 | Soft | 6 to 29 | 969 |
| Escambia County | 16 | 0.9 | Soft | 4 to 41 | 1,128 |
| Baker County | 13 | 0.8 | Soft | 9 to 23 | 535 |
| Liberty County | 12 | 0.7 | Soft | 8 to 23 | 270 |
Source: Water Quality Portal (USGS, EPA and state agencies), waterqualitydata.us, retrieved 2026-09-19. 2,904,346 samples across 3,110 counties.
What this means for a household in Florida
At 9.3 grains per gallon, a family of four would need a softener of about 24,000 grains to regenerate roughly weekly, using around 382 lb of salt a year. Size it for your own household.
66 of these counties include well samples, so the figures are a reasonable guide for private well water there. Municipal supplies in the same counties may be softer, because utilities often blend or treat.
Hardness follows geology rather than borders. Where a county sits on limestone or dolomite the water is hard; on granite, basalt or sandstone it is soft. That is why neighbouring counties in this table can differ by a factor of several.