Phoenix water hardness: what the city report says
Phoenix tap water is hard to very hard: 10 to 17.6 grains per gallon (172 to 302 ppm). That range comes from the City of Phoenix 2025 water quality report (PDF, opens in new tab).
Phoenix water hardness
Grains per gallon, from the City of Phoenix 2025 water quality report. Sacramento river water shown for comparison.
Where does Phoenix water come from?
The city's report says about 97 to 99 percent of Phoenix's water in 2025 was surface water, most of it from snowpack. The main sources are the Salt, Verde and Colorado rivers. Colorado River water arrives through the Central Arizona Project canal. Salt and Verde river water comes through the Salt River Project canals. About 20 city wells supply the rest.
The report explains that hardness comes from the soils the water touches on its way to Phoenix. Different rivers touch different soils. That is why one part of the city can be 10 gpg and another closer to 17.
What this means at home
- White scale on faucets, shower heads and tile
- Spots on dishes and glassware
- Scale inside water heaters, coffee makers and evaporative coolers
- Fixtures and appliances that wear out sooner
The city's report notes that taste, odor and hardness are not regulated under drinking water health standards. Hardness is about scale, not safety.
Do you need a water softener in Phoenix?
With every part of the city above 10 grains per gallon, most homes see a clear benefit from a softener. The only question is size, and that depends on your number and your household. Get your own tap tested so the system fits.
Want filtered drinking water too? That is a different job. Read reverse osmosis vs. a water softener, or see what a softener costs.
Get a free water test in Phoenix
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Book my free water testCommon questions
Is Phoenix water hard?
Yes. The City of Phoenix 2025 water quality report lists total hardness of 172 to 302 ppm, or 10 to 17.6 grains per gallon. That is hard to very hard.
Why does Phoenix water hardness change?
Phoenix draws from the Salt, Verde and Colorado rivers and runs several treatment plants. Each source picks up different amounts of minerals, so hardness depends on which plant serves your area.
Is hard water a health concern in Phoenix?
No. The city's report says taste, odor and hardness are not regulated under drinking water health standards. Hardness is an aesthetic issue that causes scale and spots.
Keep reading
DataWater hardness by cityHow hard the tap water is in US cities, from each utility report.
City dataLas Vegas hard water: how hard is it?About 16 grains per gallon. Very hard.
GuideHow much does a water softener cost installed?Installed price ranges, running costs, and what drives the price.
GuideReverse osmosis vs. water softener: which one do you need?They do different jobs. Here is how to pick.