Cities With the Hardest Water in America (2026 Data Study)
We ranked 86 of the largest U.S. cities by utility-reported water hardness. Madison, Las Vegas and Phoenix are among the hardest; Boston and Portland are the softest.
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Water Quality Guides
Water Quality: Know What’s in Your Tap
How to test your water, read your water report, and understand the most common problems in US homes, from hard water to chlorine, iron and well water.
Essential Water Quality Guides
New to water treatment? Read these first.
Read guide →
What Is Hard Water?
What causes it, how hard is too hard, and how it affects your home.
Read guide →
How to Test Water Hardness at Home
Five easy methods, from test strips to a certified lab.
Read guide →
Water Hardness by State
Map and data for all 50 states and major US cities.
Use the tool →
Water Hardness by Zip Code
Look up the hardness for your ZIP code or city in seconds.
Read guide →
What Is TDS in Water?
Good TDS levels, testing and how to lower it.
Read guide →
Remove Hard Water Stains
Glass, faucets, sinks and toilets, step by step.
Read guide →
How to Read Your Water Quality Report
Make sense of your city’s annual Consumer Confidence Report.
Read guide →
Well Water Testing Guide
What to test for, how often, and where to send samples.
Common Water Problems in US Homes
Match what you see at home to the likely cause and the usual fix.
Hard Water
White scale, spotty dishes, poor lather, dry skin. Caused by calcium and magnesium.
Fix: water softener →
Chlorine Taste & Smell
Pool-like smell in city water. Utilities add chlorine to keep water safe from germs.
Fix: carbon filter →
Iron & Rust Stains
Orange or brown stains in sinks, toilets and laundry. Common in well water.
Fix: iron filter or softener
Unknown Contaminants
Worried about lead, nitrate or PFAS? You can’t see, taste or smell most of them.
Fix: certified lab test first| What you notice | Likely cause | Usual fix |
|---|---|---|
| White crust on faucets, spots on glass | Hardness (calcium, magnesium) | Water softener |
| Swimming-pool smell or taste | Chlorine or chloramine | Carbon filter |
| Orange or brown stains | Iron | Iron filter or softener |
| Black stains or specks | Manganese | Manganese or oxidizing filter |
| Rotten-egg smell | Hydrogen sulfide | Oxidizing or carbon filter |
| Cloudy water that clears from the bottom up | Tiny air bubbles (usually harmless) | None needed |
| Blue-green stains | Corrosive water reacting with copper pipes | Test pH; neutralizer |
Iron starts to stain at about 0.3 mg/L and manganese at about 0.05 mg/L, the EPA’s secondary (non-health) guidelines.
City Water vs Well Water
Where your water comes from changes who tests it and what to watch for.
City waterTested by your utility
- Treated and tested to meet EPA drinking water standards
- Results published every year in a Consumer Confidence Report
- Common issues: chlorine taste, hardness, old lead service lines
Private wellTested by you
- Not covered by federal drinking water rules; the owner is responsible
- Health agencies advise testing at least once a year
- Common issues: hardness, iron, bacteria, nitrate
Free and easy
Check Your Water Quality Report
Most US community water systems must send customers an annual Consumer Confidence Report (CCR). It lists what was found in your water and how it compares with EPA limits.
Where to find itSearch your water utility’s name + “water quality report”, look at your water bill, or use the EPA’s CCR search tool. Hardness is often listed in mg/L or grains per gallon.
Want an exact number for your own tap? Use a home hardness test.
Water Quality FAQ
How do I know if my tap water is safe?
If you are on city water, read your utility’s annual Consumer Confidence Report, which shows test results against EPA limits. If you have a private well, the only way to know is to test it, ideally once a year with a certified lab.
Is hard water a water quality problem?
Hard water is not a health risk, so it is treated as an aesthetic issue. It causes scale, spots and dry skin, but the EPA sets no health limit for hardness.
Can I see or taste contaminants in my water?
Some problems, like iron, chlorine and sulfur, are easy to notice. Others, such as lead, nitrate and PFAS, have no color, taste or smell, so only a test can find them.
Does boiling water make it safe?
Boiling kills germs, which is why it is used during boil-water notices. It does not remove lead, nitrate or other chemicals, and it can concentrate them as water evaporates.
Have a question about your water?
Tell us what you are seeing at home and we may cover it in an upcoming guide.
Latest Guides
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Coliform Bacteria in Well Water: What It Means and What to Do
What a positive coliform or E. coli test means for your well, what to do right away and how to make the water safe again.
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Well Water Smells Like Sulfur (Rotten Eggs)? Causes and Fixes
Why well water smells like rotten eggs, how to find the source, and which treatment removes the sulfur smell.
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Water Test Results Checker: What Do Your Numbers Mean?
Enter your pH, hardness, TDS, iron, lead, nitrate and other results to see how they compare with EPA drinking water limits and what to do next.
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How to Remove Hard Water Stains From Every Surface
How to remove hard water stains from glass shower doors, faucets, sinks, toilets and dishes, plus how to stop them coming back.
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What Is TDS in Water? Good Levels, Testing and How to Lower It
What TDS in water means, what a good TDS level is for drinking water, how to test it and how to lower it.
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How to Remove Iron From Well Water (5 Proven Methods)
How to remove iron from well water: the types of iron, how to test, and the best and cheapest treatment options.
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Hard Water vs Soft Water: What Is the Difference?
Hard water vs soft water compared: minerals, effects on your home, skin, hair and health, and how to tell which one you have.
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Water Hardness by Zip Code: Free Lookup Tool
Look up the water hardness for your ZIP code or city in seconds, with utility-reported data for about 40,000 US ZIP codes.
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Well Water Testing: What to Test, How Often and Cost
A complete guide to private well water testing: what to test for, how often, how to sample, what it costs and what to do with your results.
