Austin water hardness: 5.4 grains per gallon
Austin tap water is moderately hard: about 5.4 grains per gallon (93 ppm) on average. Austin Water's 2025 water quality report (opens in new tab) shows a range of 4.1 to 7.4 grains per gallon across the year.
Austin water hardness
Grains per gallon, from Austin Water's 2025 water quality report. Sacramento river water shown for comparison.
Where does Austin water come from?
Austin Water draws surface water from the Lower Colorado River as it flows through Lake Travis and Lake Austin. It is treated at three plants: Handcox, Davis and Ullrich. River water usually carries fewer minerals than water pumped from limestone aquifers. That is a big reason Austin is so much softer than San Antonio, just 80 miles away.
Austin Water also posts monthly and quarterly summaries with the latest hardness numbers, so you can check the current level any time.
What 5.4 grains per gallon means at home
- Some spots on glasses, mostly if they air-dry
- Light scale on faucets over time
- Hardness that can creep higher during part of the year, up to about 7.4 gpg
Do you need a water softener in Austin?
Honestly, many Austin homes do not. At 5.4 grains per gallon, a softener is a judgment call. It is worth it if your own tap tests above about 7 grains per gallon, or if scale really bothers you. If your main concern is how your water tastes, a reverse osmosis system for drinking water may be the better buy.
Not sure? Read Do I need a softener with city water? and get your own tap tested before you spend money.
Get a free water test in Austin
Enter your ZIP code and we match you with a trusted local water specialist who tests your tap for free. If you do not need a softener, they should tell you.
Book my free water testCommon questions
Is Austin water hard?
It is moderately hard. Austin Water's 2025 report lists total hardness averaging 93 ppm, or 5.4 grains per gallon, with a range of 4.1 to 7.4 grains per gallon.
Do I need a water softener in Austin?
Often not. At about 5.4 grains per gallon, many homes are fine without one. A softener makes more sense if your test comes back above 7 grains per gallon or you fight heavy scale.
Why is Austin water softer than San Antonio?
Austin Water draws surface water from the Lower Colorado River through Lake Travis and Lake Austin. San Antonio relies heavily on limestone aquifers, which add more calcium.
Keep reading
DataWater hardness by cityHow hard the tap water is in US cities, from each utility report.
City dataSan Antonio hard water: 15 to 20 grains per gallon15 to 20 grains per gallon. Very hard.
GuideDo I need a water softener with city water?It depends on your city. Here is how to decide.
GuideReverse osmosis vs. water softener: which one do you need?They do different jobs. Here is how to pick.