Water hardness in Arkansas
Arkansas has a median ambient water hardness of 62 mg/L, which is 3.6 grains per gallon and classes as moderately hard. That is the middle of 96,554 samples across 75 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 Arkansas
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 |
|---|---|---|---|---|---|
| Fulton County | 220 | 12.9 | Very hard | 193 to 237 | 1,086 |
| Sharp County | 205 | 12 | Very hard | 160 to 238 | 862 |
| Lawrence County | 195 | 11.4 | Very hard | 160 to 220 | 1,233 |
| Boone County | 173 | 10.1 | Hard | 150 to 190 | 1,139 |
| Randolph County | 170 | 9.9 | Hard | 140 to 200 | 1,818 |
| Poinsett County | 170 | 9.9 | Hard | 120 to 200 | 560 |
| Crittenden County | 170 | 9.9 | Hard | 83 to 250 | 300 |
| Mississippi County | 170 | 9.9 | Hard | 100 to 230 | 444 |
| Baxter County | 160 | 9.3 | Hard | 139 to 180 | 2,416 |
| Izard County | 149 | 8.7 | Hard | 132 to 180 | 557 |
| Jackson County | 140 | 8.2 | Hard | 120 to 160 | 1,161 |
| Little River County | 140 | 8.2 | Hard | 60 to 250 | 1,356 |
| Marion County | 138 | 8.1 | Hard | 126 to 165 | 1,574 |
| Independence County | 137 | 8 | Hard | 110 to 150 | 752 |
| Stone County | 137 | 8 | Hard | 124 to 146 | 1,005 |
| Chicot County | 120 | 7 | Moderately hard | 53 to 250 | 309 |
| Carroll County | 118 | 6.9 | Moderately hard | 72 to 147 | 2,864 |
| Sebastian County | 118 | 6.9 | Moderately hard | 71 to 146 | 1,418 |
| Prairie County | 110 | 6.4 | Moderately hard | 61 to 140 | 1,054 |
| Benton County | 110 | 6.4 | Moderately hard | 68 to 135 | 3,779 |
| Cross County | 108 | 6.3 | Moderately hard | 45 to 170 | 594 |
| Searcy County | 107 | 6.3 | Moderately hard | 80 to 130 | 1,015 |
| Clay County | 103 | 6 | Moderately hard | 75 to 138 | 623 |
| Arkansas County | 100 | 5.8 | Moderately hard | 59 to 138 | 1,417 |
| Monroe County | 98 | 5.7 | Moderately hard | 54 to 150 | 1,790 |
| Lee County | 98 | 5.7 | Moderately hard | 55 to 160 | 499 |
| Phillips County | 96 | 5.6 | Moderately hard | 61 to 179 | 142 |
| St. Francis County | 95 | 5.5 | Moderately hard | 54 to 162 | 1,019 |
| Franklin County | 89 | 5.2 | Moderately hard | 16 to 140 | 788 |
| Miller County | 86 | 5 | Moderately hard | 60 to 210 | 1,592 |
| Madison County | 84 | 4.9 | Moderately hard | 54 to 118 | 1,251 |
| Washington County | 84 | 4.9 | Moderately hard | 51 to 130 | 4,404 |
| Desha County | 81 | 4.7 | Moderately hard | 28 to 150 | 810 |
| Newton County | 81 | 4.7 | Moderately hard | 36 to 135 | 489 |
| Lonoke County | 80 | 4.7 | Moderately hard | 37 to 142 | 599 |
| Jefferson County | 75 | 4.4 | Moderately hard | 29 to 130 | 1,986 |
| Craighead County | 75 | 4.4 | Moderately hard | 44 to 106 | 1,064 |
| Conway County | 74 | 4.3 | Moderately hard | 13 to 134 | 850 |
| Union County | 72 | 4.2 | Moderately hard | 34 to 180 | 4,413 |
| Pulaski County | 65 | 3.8 | Moderately hard | 27 to 137 | 4,969 |
| Pope County | 58 | 3.4 | Soft | 14 to 150 | 3,476 |
| Woodruff County | 55 | 3.2 | Soft | 32 to 109 | 1,086 |
| Saline County | 51 | 3 | Soft | 28 to 63 | 2,159 |
| Lincoln County | 47 | 2.7 | Soft | 20 to 121 | 583 |
| Greene County | 45 | 2.6 | Soft | 17 to 160 | 87 |
| Faulkner County | 44 | 2.6 | Soft | 15 to 80 | 1,170 |
| Dallas County | 40 | 2.3 | Soft | 20 to 56 | 750 |
| Grant County | 38 | 2.2 | Soft | 22 to 60 | 1,117 |
| Lafayette County | 30 | 1.8 | Soft | 18 to 76 | 731 |
| Ashley County | 30 | 1.8 | Soft | 16 to 44 | 769 |
| Drew County | 29 | 1.7 | Soft | 18 to 40 | 508 |
| Hempstead County | 28 | 1.6 | Soft | 19 to 64 | 596 |
| Cleveland County | 28 | 1.6 | Soft | 22 to 37 | 555 |
| Bradley County | 26 | 1.5 | Soft | 16 to 37 | 717 |
| Clark County | 26 | 1.5 | Soft | 20 to 34 | 1,892 |
| Hot Spring County | 25 | 1.5 | Soft | 20 to 49 | 1,921 |
| Nevada County | 24 | 1.4 | Soft | 17 to 35 | 680 |
| Garland County | 24 | 1.4 | Soft | 20 to 46 | 1,052 |
| Logan County | 23 | 1.3 | Soft | 17 to 36 | 1,125 |
| Ouachita County | 23 | 1.3 | Soft | 19 to 29 | 1,160 |
| Montgomery County | 22 | 1.3 | Soft | 16 to 30 | 1,209 |
| Columbia County | 21 | 1.2 | Soft | 14 to 32 | 598 |
| Scott County | 20 | 1.2 | Soft | 13 to 33 | 1,321 |
| Johnson County | 19 | 1.1 | Soft | 11 to 60 | 357 |
| Yell County | 18 | 1.1 | Soft | 12 to 26 | 1,921 |
| Crawford County | 18 | 1.1 | Soft | 13 to 42 | 784 |
| White County | 18 | 1.1 | Soft | 15 to 25 | 883 |
| Cleburne County | 17 | 1 | Soft | 15 to 22 | 1,306 |
| Sevier County | 17 | 1 | Soft | 12 to 24 | 2,623 |
| Howard County | 16 | 0.9 | Soft | 11 to 26 | 2,362 |
| Pike County | 16 | 0.9 | Soft | 11 to 24 | 961 |
| Van Buren County | 14 | 0.8 | Soft | 8 to 34 | 1,296 |
| Polk County | 14 | 0.8 | Soft | 10 to 22 | 1,243 |
| Perry County | 12 | 0.7 | Soft | 9 to 18 | 1,132 |
| Calhoun County | 12 | 0.7 | Soft | 9 to 18 | 423 |
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 Arkansas
At 3.6 grains per gallon, a family of four would need a softener of about 16,000 grains to regenerate roughly weekly, using around 149 lb of salt a year. Size it for your own household.
75 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.