National hardness map
U.S. Water Hardness Map
Compare average water hardness by state, filter by source profile and hardness class, then search for local ZIP, city, and public water system reports.
Explore state hardness and source coverage
Compare states by hardness class and dominant source profile, then open local reports for ZIP, city, and utility-level detail.
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
softslightly hardmoderately hardhardvery hard
Hardest matching state averages
| State | Average | Source profile | Verified ZIPs |
|---|---|---|---|
| South Dakota 354 cities · 463 systems | Very Hard (441 PPM) | Estimate-heavy | 76 / 362 |
| North Dakota 370 cities · 305 systems | Very Hard (364 PPM) | USGS-led | 114 / 374 |
| Nebraska 516 cities · 585 systems | Very Hard (333 PPM) | USGS-led | 102 / 569 |
| Indiana 662 cities · 771 systems | Very Hard (325 PPM) | USGS-led | 266 / 752 |
| Kansas 623 cities · 856 systems | Very Hard (318 PPM) | Estimate-heavy | 153 / 685 |
| Iowa 899 cities · 1,076 systems | Very Hard (302 PPM) | USGS-led | 355 / 937 |
| Colorado 386 cities · 1,048 systems | Very Hard (299 PPM) | Treated-water led | 224 / 478 |
| Wyoming 156 cities · 323 systems | Very Hard (298 PPM) | USGS-led | 32 / 165 |
Softest matching state averages
| State | Average | Source profile | Verified ZIPs |
|---|---|---|---|
| Massachusetts 404 cities · 525 systems | Soft (23 PPM) | Treated-water led | 373 / 496 |
| South Carolina 340 cities · 564 systems | Soft (37 PPM) | Treated-water led | 161 / 396 |
| New Hampshire 217 cities · 710 systems | Soft (39 PPM) | USGS-led | 74 / 226 |
| Hawaii 76 cities · 119 systems | Soft (45 PPM) | Treated-water led | 57 / 87 |
| Oregon 358 cities · 934 systems | Soft (47 PPM) | Treated-water led | 184 / 400 |
| North Carolina 684 cities · 1,979 systems | Soft (52 PPM) | USGS-led | 221 / 778 |
| Maine 388 cities · 387 systems | Soft (53 PPM) | Treated-water led | 192 / 390 |
| Connecticut 222 cities · 475 systems | Soft (57 PPM) | USGS-led | 0 / 262 |
State coverage table
Verified ZIP coverage counts direct treated-water sources. Other ZIPs can still use USGS monitoring or estimated source labels.
| State | Average | Source profile | Verified ZIPs |
|---|---|---|---|
| South Dakota 354 cities · 463 systems | Very Hard (441 PPM) | Estimate-heavy | 76 / 362 |
| North Dakota 370 cities · 305 systems | Very Hard (364 PPM) | USGS-led | 114 / 374 |
| Nebraska 516 cities · 585 systems | Very Hard (333 PPM) | USGS-led | 102 / 569 |
| Indiana 662 cities · 771 systems | Very Hard (325 PPM) | USGS-led | 266 / 752 |
| Kansas 623 cities · 856 systems | Very Hard (318 PPM) | Estimate-heavy | 153 / 685 |
| Iowa 899 cities · 1,076 systems | Very Hard (302 PPM) | USGS-led | 355 / 937 |
| Colorado 386 cities · 1,048 systems | Very Hard (299 PPM) | Treated-water led | 224 / 478 |
| Wyoming 156 cities · 323 systems | Very Hard (298 PPM) | USGS-led | 32 / 165 |
| Oklahoma 561 cities · 889 systems | Very Hard (296 PPM) | Estimate-heavy | 179 / 646 |
| Minnesota 783 cities · 965 systems | Very Hard (293 PPM) | Estimate-heavy | 241 / 853 |
| Utah 242 cities · 507 systems | Very Hard (290 PPM) | Treated-water led | 141 / 272 |
| Montana 335 cities · 792 systems | Very Hard (260 PPM) | Estimate-heavy | 142 / 346 |
| Illinois 1,231 cities · 1,782 systems | Very Hard (254 PPM) | Treated-water led | 488 / 1,335 |
| New Mexico 315 cities · 555 systems | Very Hard (251 PPM) | USGS-led | 101 / 339 |
| Ohio 994 cities · 1,128 systems | Hard (239 PPM) | USGS-led | 421 / 1,144 |
| Wisconsin 703 cities · 1,021 systems | Hard (237 PPM) | Treated-water led | 267 / 760 |
| Arizona 228 cities · 751 systems | Hard (236 PPM) | Treated-water led | 195 / 344 |
| Missouri 903 cities · 1,431 systems | Hard (219 PPM) | USGS-led | 346 / 997 |
| Texas 1,376 cities · 4,713 systems | Hard (210 PPM) | Treated-water led | 901 / 1,843 |
| West Virginia 690 cities · 412 systems | Hard (197 PPM) | USGS-led | 247 / 701 |
| Michigan 829 cities · 1,381 systems | Hard (188 PPM) | Treated-water led | 424 / 955 |
| Nevada 86 cities · 192 systems | Moderately Hard (178 PPM) | Treated-water led | 83 / 143 |
| Florida 512 cities · 1,593 systems | Moderately Hard (165 PPM) | Treated-water led | 601 / 913 |
| California 1,170 cities · 2,819 systems | Moderately Hard (159 PPM) | Treated-water led | 1,404 / 1,661 |
| Idaho 252 cities · 764 systems | Moderately Hard (157 PPM) | USGS-led | 64 / 267 |
| Tennessee 513 cities · 446 systems | Moderately Hard (144 PPM) | Estimate-heavy | 205 / 602 |
| New York 1,362 cities · 2,245 systems | Moderately Hard (137 PPM) | USGS-led | 616 / 1,611 |
| Kentucky 702 cities · 374 systems | Moderately Hard (127 PPM) | Estimate-heavy | 136 / 739 |
| District of Columbia 2 cities · 4 systems | Moderately Hard (120 PPM) | Treated-water led | 23 / 23 |
| Pennsylvania 1,579 cities · 1,855 systems | Slightly Hard (115 PPM) | USGS-led | 620 / 1,693 |
| Maryland 399 cities · 461 systems | Slightly Hard (95 PPM) | Treated-water led | 225 / 450 |
| Arkansas 557 cities · 665 systems | Slightly Hard (94 PPM) | USGS-led | 204 / 582 |
| Louisiana 441 cities · 917 systems | Slightly Hard (91 PPM) | USGS-led | 142 / 510 |
| Washington 452 cities · 2,311 systems | Slightly Hard (90 PPM) | Treated-water led | 293 / 561 |
| Delaware 56 cities · 207 systems | Slightly Hard (86 PPM) | Treated-water led | 64 / 64 |
| Mississippi 374 cities · 1,012 systems | Slightly Hard (84 PPM) | USGS-led | 65 / 404 |
| Vermont 248 cities · 405 systems | Slightly Hard (75 PPM) | Estimate-heavy | 66 / 249 |
| Virginia 711 cities · 1,062 systems | Slightly Hard (74 PPM) | Treated-water led | 403 / 857 |
| New Jersey 522 cities · 555 systems | Slightly Hard (73 PPM) | Treated-water led | 522 / 577 |
| Alabama 528 cities · 501 systems | Slightly Hard (72 PPM) | Estimate-heavy | 220 / 613 |
| Alaska 222 cities · 405 systems | Slightly Hard (71 PPM) | Estimate-heavy | 37 / 237 |
| Georgia 539 cities · 1,739 systems | Slightly Hard (61 PPM) | USGS-led | 182 / 671 |
| Rhode Island 50 cities · 89 systems | Soft (60 PPM) | Treated-water led | 43 / 70 |
| Connecticut 222 cities · 475 systems | Soft (57 PPM) | USGS-led | 0 / 262 |
| Maine 388 cities · 387 systems | Soft (53 PPM) | Treated-water led | 192 / 390 |
| North Carolina 684 cities · 1,979 systems | Soft (52 PPM) | USGS-led | 221 / 778 |
| Oregon 358 cities · 934 systems | Soft (47 PPM) | Treated-water led | 184 / 400 |
| Hawaii 76 cities · 119 systems | Soft (45 PPM) | Treated-water led | 57 / 87 |
| New Hampshire 217 cities · 710 systems | Soft (39 PPM) | USGS-led | 74 / 226 |
| South Carolina 340 cities · 564 systems | Soft (37 PPM) | Treated-water led | 161 / 396 |
| Massachusetts 404 cities · 525 systems | Soft (23 PPM) | Treated-water led | 373 / 496 |