Water hardness · by city
Hard Water by City: How Hard Is Your Tap Water?
Hardness for 42 US cities, in grains per gallon, from each utility's own water-quality report. Hardness affects scale and appliances; it is not a health finding.
Only cities with a utility report on file are listed. A city missing here is not soft; its hardness simply is not published yet.
Cities ranked by hardnessHardest first. Bands: soft under 1 gpg, slightly hard 1-3.5, moderately hard 3.5-7, hard 7-10.5, very hard above 10.5.
| # | City | Hardness | Band |
|---|---|---|---|
| 1 | San AntonioTX | 17.5 gpg299 mg/L | Very hard |
| 2 | Las VegasNV | 16.4 gpg280 mg/L | Very hard |
| 3 | AllentownPA | 15 gpg257 mg/L | Very hard |
| 4 | PhoenixAZ | 14.7 gpg251 mg/L | Very hard |
| 5 | ScottsdaleAZ | 14.6 gpg250 mg/L | Very hard |
| 6 | MesaAZ | 14 gpg239 mg/L | Very hard |
| 7 | AmarilloTX | 13.9 gpg238 mg/L | Very hard |
| 8 | San DiegoCA | 12.9 gpg221 mg/L | Very hard |
| 9 | TampaFL | 12.3 gpg210 mg/L | Very hard |
| 10 | RiversideCA | 11.3 gpg193 mg/L | Very hard |
| 11 | LincolnNE | 11.2 gpg192 mg/L | Very hard |
| 12 | El PasoTX | 10.2 gpg174 mg/L | Hard |
| 13 | FriscoTX | 10.2 gpg174 mg/L | Hard |
| 14 | Long BeachCA | 10.2 gpg174 mg/L | Hard |
| 15 | LubbockTX | 9.9 gpg169 mg/L | Hard |
| 16 | St. PetersburgFL | 9.6 gpg164 mg/L | Hard |
| 17 | OmahaNE | 9 gpg154 mg/L | Hard |
| 18 | ChicagoIL | 8.2 gpg140 mg/L | Hard |
| 19 | Los AngelesCA | 8.2 gpg140 mg/L | Hard |
| 20 | PhiladelphiaPA | 8.2 gpg140 mg/L | Hard |
| 21 | SacramentoCA | 8.1 gpg139 mg/L | Hard |
| 22 | HoustonTX | 7.9 gpg135 mg/L | Hard |
| 23 | Fort WayneIN | 7.6 gpg130 mg/L | Hard |
| 24 | HuntsvilleAL | 7.6 gpg130 mg/L | Hard |
| 25 | EriePA | 7 gpg120 mg/L | Moderately hard |
| 26 | ClevelandOH | 6.8 gpg116 mg/L | Moderately hard |
| 27 | Iowa CityIA | 6.5 gpg111 mg/L | Moderately hard |
| 28 | BoiseID | 6.3 gpg108 mg/L | Moderately hard |
| 29 | DenverCO | 6.1 gpg104 mg/L | Moderately hard |
| 30 | MinneapolisMN | 5.7 gpg97 mg/L | Moderately hard |
| 31 | AustinTX | 5.4 gpg92 mg/L | Moderately hard |
| 32 | BuffaloNY | 5.2 gpg89 mg/L | Moderately hard |
| 33 | ChattanoogaTN | 4.4 gpg75 mg/L | Moderately hard |
| 34 | Jersey CityNJ | 4.4 gpg75 mg/L | Moderately hard |
| 35 | RichmondVA | 3.6 gpg62 mg/L | Moderately hard |
| 36 | CharlotteNC | 1.9 gpg32 mg/L | Soft |
| 37 | New York CityNY | 1.9 gpg32 mg/L | Soft |
| 38 | SeattleWA | 1.8 gpg31 mg/L | Soft |
| 39 | WorcesterMA | 1.8 gpg31 mg/L | Soft |
| 40 | CaryNC | 1.6 gpg27 mg/L | Soft |
| 41 | KirklandWA | 1.5 gpg26 mg/L | Soft |
| 42 | AshevilleNC | 0.3 gpg5 mg/L | Soft |
Does your state have hard water?Answered only from the cities in that state with a utility hardness value on file.
- AlabamaHuntsville: 7.6 gpg
- Arizona3 cities, 14 gpg (Mesa) to 14.7 gpg (Phoenix)
- California5 cities, 8.1 gpg (Sacramento) to 12.9 gpg (San Diego)
- ColoradoDenver: 6.1 gpg
- Florida2 cities, 9.6 gpg (St. Petersburg) to 12.3 gpg (Tampa)
- IdahoBoise: 6.3 gpg
- IllinoisChicago: 8.2 gpg
- IndianaFort Wayne: 7.6 gpg
- IowaIowa City: 6.5 gpg
- MassachusettsWorcester: 1.8 gpg
- MinnesotaMinneapolis: 5.7 gpg
- Nebraska2 cities, 9 gpg (Omaha) to 11.2 gpg (Lincoln)
- NevadaLas Vegas: 16.4 gpg
- New JerseyJersey City: 4.4 gpg
- New York2 cities, 1.9 gpg (New York City) to 5.2 gpg (Buffalo)
- North Carolina3 cities, 0.3 gpg (Asheville) to 1.9 gpg (Charlotte)
- OhioCleveland: 6.8 gpg
- Pennsylvania3 cities, 7 gpg (Erie) to 15 gpg (Allentown)
- TennesseeChattanooga: 4.4 gpg
- Texas7 cities, 5.4 gpg (Austin) to 17.5 gpg (San Antonio)
- VirginiaRichmond: 3.6 gpg
- Washington2 cities, 1.5 gpg (Kirkland) to 1.8 gpg (Seattle)
What to do about hard water
An ion-exchange water softener removes calcium and magnesium for the whole home and is the proven fix for scale; it adds some sodium and needs salt refills. Salt-free conditioners change how minerals form scale rather than removing them. Neither is a health treatment, and neither removes PFAS or lead.
Frequently asked questions
Which US cities have the hardest tap water?
Among the 42 cities whose utility reports give a hardness value, the hardest are San Antonio, TX (17.5 gpg), Las Vegas, NV (16.4 gpg), Allentown, PA (15 gpg). Many more cities have hard water; PurityMap lists only those with a utility report on file.
What is hard water?
Hard water carries dissolved calcium and magnesium picked up from rock and soil, most often in groundwater. It is measured in grains per gallon (gpg) or mg/L as calcium carbonate; 1 gpg is 17.1 mg/L. Above about 7 gpg is generally considered hard, and above 10.5 gpg very hard.
Is hard water a health concern?
Hardness has no federal health-based limit. It causes scale on fixtures, water heaters and appliances and makes soap lather less, which is why it is treated as an aesthetic and maintenance issue. Softening adds some sodium, which matters for people on low-sodium diets.
How do I find my water hardness?
Your utility's annual Consumer Confidence Report (water quality report) usually lists hardness. Home test strips give a quick reading, and a city page here shows the utility's value where the report is on file.