National hardness map
U.S. Water Hardness Map
Compare average water hardness by state, then open state or ZIP reports for local PPM, GPG, source confidence, and matched water systems.
SD441 PPMND364 PPMNE333 PPMIN325 PPMKS318 PPMIA302 PPMCO299 PPMWY298 PPMOK296 PPMMN293 PPMUT290 PPMMT260 PPMIL254 PPMNM251 PPMOH239 PPMWI237 PPMAZ236 PPMMO219 PPMTX210 PPMWV197 PPMMI188 PPMNV178 PPMFL165 PPMCA159 PPMID157 PPMTN144 PPMNY137 PPMKY127 PPMDC120 PPMPA115 PPMMD95 PPMAR94 PPMLA91 PPMWA90 PPMDE86 PPMMS84 PPMVT75 PPMVA74 PPMNJ73 PPMAL72 PPMAK71 PPMGA61 PPMRI60 PPMCT57 PPMME53 PPMNC52 PPMOR47 PPMHI45 PPMNH39 PPMSC37 PPMMA23 PPM
softmoderatehardvery hard
Hardest State Averages
1.South Dakota354 citiesVery Hard (441 PPM)2.North Dakota370 citiesVery Hard (364 PPM)3.Nebraska516 citiesVery Hard (333 PPM)4.Indiana662 citiesVery Hard (325 PPM)5.Kansas623 citiesVery Hard (318 PPM)6.Iowa899 citiesVery Hard (302 PPM)7.Colorado386 citiesVery Hard (299 PPM)8.Wyoming156 citiesVery Hard (298 PPM)9.Oklahoma561 citiesVery Hard (296 PPM)10.Minnesota783 citiesVery Hard (293 PPM)
Softest State Averages
1.Massachusetts404 citiesSoft (23 PPM)2.South Carolina340 citiesSoft (37 PPM)3.New Hampshire217 citiesSoft (39 PPM)4.Hawaii76 citiesSoft (45 PPM)5.Oregon358 citiesSoft (47 PPM)6.North Carolina684 citiesSoft (52 PPM)7.Maine388 citiesSoft (53 PPM)8.Connecticut222 citiesSoft (57 PPM)9.Rhode Island50 citiesSoft (60 PPM)10.Georgia539 citiesSlightly Hard (61 PPM)
State Coverage Table
Verified ZIP coverage counts direct treated-water sources. Other ZIPs can still use USGS or estimated source labels.
| State | Average | Systems | Verified ZIPs |
|---|---|---|---|
| South Dakota | Very Hard (441 PPM) | 463 | 76 / 362 |
| North Dakota | Very Hard (364 PPM) | 305 | 114 / 374 |
| Nebraska | Very Hard (333 PPM) | 585 | 102 / 569 |
| Indiana | Very Hard (325 PPM) | 771 | 266 / 752 |
| Kansas | Very Hard (318 PPM) | 856 | 153 / 685 |
| Iowa | Very Hard (302 PPM) | 1,076 | 355 / 937 |
| Colorado | Very Hard (299 PPM) | 1,048 | 224 / 478 |
| Wyoming | Very Hard (298 PPM) | 323 | 32 / 165 |
| Oklahoma | Very Hard (296 PPM) | 889 | 179 / 646 |
| Minnesota | Very Hard (293 PPM) | 965 | 241 / 853 |
| Utah | Very Hard (290 PPM) | 507 | 141 / 272 |
| Montana | Very Hard (260 PPM) | 792 | 142 / 346 |
| Illinois | Very Hard (254 PPM) | 1,782 | 488 / 1,335 |
| New Mexico | Very Hard (251 PPM) | 555 | 101 / 339 |
| Ohio | Hard (239 PPM) | 1,128 | 421 / 1,144 |
| Wisconsin | Hard (237 PPM) | 1,021 | 267 / 760 |
| Arizona | Hard (236 PPM) | 751 | 195 / 344 |
| Missouri | Hard (219 PPM) | 1,431 | 346 / 997 |
| Texas | Hard (210 PPM) | 4,713 | 901 / 1,843 |
| West Virginia | Hard (197 PPM) | 412 | 247 / 701 |
| Michigan | Hard (188 PPM) | 1,381 | 424 / 955 |
| Nevada | Moderately Hard (178 PPM) | 192 | 83 / 143 |
| Florida | Moderately Hard (165 PPM) | 1,593 | 601 / 913 |
| California | Moderately Hard (159 PPM) | 2,819 | 1,404 / 1,661 |
| Idaho | Moderately Hard (157 PPM) | 764 | 64 / 267 |
| Tennessee | Moderately Hard (144 PPM) | 446 | 205 / 602 |
| New York | Moderately Hard (137 PPM) | 2,245 | 616 / 1,611 |
| Kentucky | Moderately Hard (127 PPM) | 374 | 136 / 739 |
| District of Columbia | Moderately Hard (120 PPM) | 4 | 23 / 23 |
| Pennsylvania | Slightly Hard (115 PPM) | 1,855 | 620 / 1,693 |
| Maryland | Slightly Hard (95 PPM) | 461 | 225 / 450 |
| Arkansas | Slightly Hard (94 PPM) | 665 | 204 / 582 |
| Louisiana | Slightly Hard (91 PPM) | 917 | 142 / 510 |
| Washington | Slightly Hard (90 PPM) | 2,311 | 293 / 561 |
| Delaware | Slightly Hard (86 PPM) | 207 | 64 / 64 |
| Mississippi | Slightly Hard (84 PPM) | 1,012 | 65 / 404 |
| Vermont | Slightly Hard (75 PPM) | 405 | 66 / 249 |
| Virginia | Slightly Hard (74 PPM) | 1,062 | 403 / 857 |
| New Jersey | Slightly Hard (73 PPM) | 555 | 522 / 577 |
| Alabama | Slightly Hard (72 PPM) | 501 | 220 / 613 |
| Alaska | Slightly Hard (71 PPM) | 405 | 37 / 237 |
| Georgia | Slightly Hard (61 PPM) | 1,739 | 182 / 671 |
| Rhode Island | Soft (60 PPM) | 89 | 43 / 70 |
| Connecticut | Soft (57 PPM) | 475 | 0 / 262 |
| Maine | Soft (53 PPM) | 387 | 192 / 390 |
| North Carolina | Soft (52 PPM) | 1,979 | 221 / 778 |
| Oregon | Soft (47 PPM) | 934 | 184 / 400 |
| Hawaii | Soft (45 PPM) | 119 | 57 / 87 |
| New Hampshire | Soft (39 PPM) | 710 | 74 / 226 |
| South Carolina | Soft (37 PPM) | 564 | 161 / 396 |
| Massachusetts | Soft (23 PPM) | 525 | 373 / 496 |