30 US Cities With the Hardest Water
Ranked by grains per gallon (GPG) using data from official municipal water quality reports. Updated for 2026.
Quick Reference
| # | City | GPG | PPM | Level |
|---|---|---|---|---|
| 1 | Midland, TX City of Midland | 29.3 | 500 | Very Hard |
| 2 | San Antonio, TX SAWS | 21 | 357 | Very Hard |
| 3 | Las Vegas, NV LVVWD | 18 | 304 | Very Hard |
| 4 | Indianapolis, IN Citizens Energy | 17.5 | 300 | Very Hard |
| 5 | Henderson, NV City of Henderson | 17 | 300 | Very Hard |
| 6 | Wichita, KS City of Wichita Water | 17 | 291 | Very Hard |
| 7 | North Las Vegas, NV LVVWD | 17 | 291 | Very Hard |
| 8 | Boulder City, NV Boulder City Utilities | 17 | 290 | Very Hard |
| 9 | Scottsdale, AZ Scottsdale Water Resources | 16 | 280 | Very Hard |
| 10 | Columbus, OH Columbus Division of Water | 16 | 275 | Very Hard |
| 11 | Tampa, FL Tampa Water Department | 16 | 275 | Very Hard |
| 12 | Jacksonville, FL JEA | 15.5 | 266 | Very Hard |
| 13 | Kansas City, MO KC Water | 15 | 257 | Very Hard |
| 14 | Phoenix, AZ City of Phoenix Water Services | 15 | 250 | Very Hard |
| 15 | Lubbock, TX City of Lubbock Water Utilities | 14 | 243 | Very Hard |
| 16 | Mesa, AZ City of Mesa | 14 | 240 | Very Hard |
| 17 | Riverside, CA Riverside Public Utilities | 13.5 | 231 | Very Hard |
| 18 | Chandler, AZ City of Chandler | 13 | 230 | Very Hard |
| 19 | Glendale, AZ Glendale Water Services | 13 | 227 | Very Hard |
| 20 | Tempe, AZ City of Tempe | 13 | 224 | Very Hard |
| 21 | Minneapolis, MN Minneapolis Water | 13 | 223 | Very Hard |
| 22 | Peoria, AZ Peoria Water Services | 13 | 222 | Very Hard |
| 23 | Albuquerque, NM ABCWUA | 12.5 | 214 | Very Hard |
| 24 | Tucson, AZ Tucson Water | 12 | 211 | Very Hard |
| 25 | El Paso, TX El Paso Water Utilities | 12 | 206 | Very Hard |
| 26 | Salt Lake City, UT SLC Public Utilities | 11.5 | 197 | Very Hard |
| 27 | Oklahoma City, OK OKC Utilities | 11 | 188 | Very Hard |
| 28 | Omaha, NE MUD Omaha | 10 | 171 | Hard |
| 29 | Milwaukee, WI Milwaukee Water Works | 10 | 171 | Hard |
| 30 | Gilbert, AZ Town of Gilbert | 9 | 154 | Hard |
Why These Cities Have Such Hard Water
The hardest water in the US follows a clear geological pattern. Cities in the Southwest (Arizona, Nevada, Texas) draw from the Colorado River system and desert aquifers, both of which flow through extensive limestone and dolomite formations. The Colorado River picks up minerals across its 1,400-mile journey through the Rocky Mountains and Grand Canyon.
Florida cities like Tampa and Jacksonville sit on the Floridan Aquifer, one of the most productive limestone aquifer systems in the world, which naturally produces very hard water.
Midwest cities including Indianapolis, Columbus, and Wichita draw from glacial aquifers and limestone bedrock that covers much of the region, resulting in consistently hard water above 10 GPG.
Notably, most cities above 10 GPG would benefit from a salt-based water softener. Between 7-10 GPG, a salt-free conditioner or whole-house filter can help. Below 7 GPG, a simple shower filter is usually sufficient.
Check Your Water Hardness
Enter your ZIP code to see your exact hardness level and get treatment recommendations.
Look Up Your ZIP CodeFrequently Asked Questions
Data sourced from municipal Consumer Confidence Reports (CCRs) and EPA SDWIS records. GPG values represent annual averages; actual hardness may vary by season and location within each city.