Last updated: November 8, 2026 · Data: City of Phoenix Water Services Department water quality data via TapWaterData (CC BY 4.0)
Yes, Phoenix has very hard water. City of Phoenix Water Services Department reports total hardness of about 237 mg/L, or 13.9 grains per gallon (GPG), which is very hard on the U.S. Geological Survey scale. That ranks Phoenix #5 for hardest water among the 86 large U.S. cities in our 2026 study, and above the Arizona median of about 158 mg/L.
If you live in Phoenix, you have probably seen the signs: white crust on faucets and shower heads, spotty dishes and soap that will not lather. This guide explains where Phoenix’s water comes from, how hard it is compared with nearby cities and the rest of the country, and whether a water softener is worth it for your home.
Phoenix water hardness at a glance
- Hardness: 237 mg/L (13.9 GPG)
- Category: Very hard
- Water utility: City of Phoenix Water Services Department
- Data date: December 2025
- National rank: #5 hardest of 86 large U.S. cities
- Suggested softener hardness setting: about 16 GPG
Where Does Phoenix Get Its Water?
Phoenix gets most of its water from the Salt and Verde rivers, delivered through the Salt River Project, and from the Colorado River through the Central Arizona Project (CAP) canal, with a smaller share from groundwater wells. Hardness can change through the year and by neighborhood, depending on which treatment plant and source is serving your area at the time.
Arizona’s heat speeds up evaporation, so spots and crust form quickly on fixtures, pool tile and car finishes, and water heaters in hot climates build scale fast.
How Hard Is Phoenix Water Compared With Other Places?
| Place | Hardness (mg/L) | GPG |
|---|---|---|
| Phoenix, AZ | 237 | 13.9 |
| Arizona median | 158 | 9.2 |
| Median of 86 large U.S. cities | 112 | 6.5 |
| Hardest large city (Madison, WI) | 341 | 19.9 |
| Softest large city (Boston, MA) | 17 | 1.0 |
See the full rankings in our study of cities with the hardest water in the USA, or compare states on our US hard water map.
Water Hardness in Cities Near Phoenix
| City | Hardness (mg/L) | GPG | Category | Distance |
|---|---|---|---|---|
| Glendale | 169 | 9.9 | Hard | 8 mi |
| Tempe | 180 | 10.5 | Hard | 9 mi |
| Paradise Valley | 171 | 10 | Hard | 10 mi |
| Scottsdale | 172 | 10.1 | Hard | 11 mi |
| Mesa | 141 | 8.2 | Hard | 13 mi |
| Peoria | 168 | 9.8 | Hard | 13 mi |
| Chandler | 139 | 8.1 | Hard | 15 mi |
| Avondale | 105 | 6.1 | Moderately hard | 16 mi |
Nearby cities can have very different water because they use different utilities, wells or treatment plants.
What 13.9 GPG Hard Water Means for Your Home
- Scale: white, chalky buildup on faucets, shower heads, glass doors and inside kettles.
- Water heater: scale settles in the tank and on heating elements, lowering efficiency and shortening its life.
- Dishes and laundry: spots and film on glasses, stiff towels and faded colors.
- Skin and hair: soap scum can leave skin feeling dry and hair dull.
- Cleaning: you need more soap and detergent. See how to remove hard water stains.
Do You Need a Water Softener in Phoenix?
At 13.9 grains per gallon, most Phoenix homes will notice a big difference with a water softener. Here is a quick sizing example for a family of four using about 300 gallons a day:
- Daily hardness load: 300 gallons × 13.9 GPG = about 4,170 grains a day
- Weekly load: about 29,000 grains
- Suggested softener size: 32,000 to 40,000 grains
- Hardness setting: about 16 GPG (your hardness plus a small buffer)
- Sodium added: about 26 mg per 8-ounce glass of softened water
Learn more in how a water softener works, what size softener you need and water softener cost. If you would rather avoid salt, compare salt-free conditioners, which reduce scale but do not remove hardness.
Is Phoenix Tap Water Safe to Drink?
Hard water is not a health risk, and the EPA sets no health limit for hardness. City of Phoenix Water Services Department is required to meet EPA drinking water standards and publishes an annual water quality report (Consumer Confidence Report) with its test results. If you have your own test results, compare them with EPA limits using our water test results checker.
Check the Hardness at Your Address
Hardness can vary by neighborhood. Enter your ZIP code below to see the data for your area.
Data: TapWaterData US Water Hardness Dataset (CC BY 4.0), based on utility water quality reports. ZIP locations: GeoNames (CC BY 4.0).
Frequently Asked Questions
Does Phoenix have hard water?
Yes. Phoenix’s water is very hard, at about 237 mg/L (13.9 grains per gallon) according to City of Phoenix Water Services Department.
How hard is Phoenix water in grains per gallon?
About 13.9 grains per gallon (GPG), or 237 mg/L as calcium carbonate. Anything above 7 GPG is considered hard, and above 10.5 GPG is very hard.
What should I set my water softener to in Phoenix?
Start with about 16 GPG, which is Phoenix’s hardness plus a small buffer. If your home has iron in the water, add about 4 GPG for each 1 mg/L of iron. Test your softened water to confirm it reads close to zero.
Where does Phoenix get its drinking water?
Phoenix gets most of its water from the Salt and Verde rivers, delivered through the Salt River Project, and from the Colorado River through the Central Arizona Project (CAP) canal, with a smaller share from groundwater wells.
Is Phoenix hard water bad for you?
No. Hard water is not considered a health risk. It mainly causes scale, spotty dishes, poor soap lather and dry skin, which a water softener fixes.
Sources: City of Phoenix Water Services Department annual water quality report, via TapWaterData US Water Hardness Dataset (CC BY 4.0); USGS: Hardness of Water.