Austin’s tap water averaged 93 ppm of hardness, or 5.4 grains per gallon, in Austin Water’s 2025 water quality report, with a range of 70 to 126 ppm (4.1 to 7.4 gpg). That’s moderately hard on the USGS scale, and softer than most of Texas, because Austin Water removes part of the hardness at its treatment plants. If you run a softener, set it to about 7.4 gpg, the top of the range.
On this page
5.4 gpg 93 mg/L average · range 70–126
Austin Water, 2025 Water Quality Report. Scale: USGS classes up to 300 mg/L.
| Average hardness | 93 ppm (mg/L as CaCO3) = 5.4 gpg |
|---|---|
| Range in 2025 | 70–126 ppm = 4.1–7.4 gpg |
| USGS class | Moderately hard (61–120 mg/L); the top of the range is just into “hard” |
| Suggested softener setting | 7.4 gpg (high end of the range) |
| Source water | Lake Austin and Lake Travis |
| Treatment | Lime softening at all three plants (Davis, Ullrich, Handcox) |
| Utility | Austin Water (City of Austin) |
Why Austin water is softer than you might expect
Central Texas sits on limestone, and plenty of its groundwater is very hard: San Antonio, 80 miles south, reports 15 to 20 gpg. Austin is different for two reasons.
First, it draws surface water. Austin Water takes its raw water from Lake Austin and Lake Travis, the reservoirs on the Colorado River, and treats it at three plants: Davis (118 million gallons a day), Ullrich (167 million) and Handcox (50 million).
Second, it softens that water before you get it. An external review of Austin’s water quality events, published by the City Auditor in 2023, states that “all the Austin WTPs use a lime softening process”. Lime softening raises the pH so calcium carbonate precipitates out and settles, which is why Austin’s tap water lands in the moderately hard band rather than higher.
Austin water hardness in other units
| Unit | Low (70 ppm) | Average (93 ppm) | High (126 ppm) |
|---|---|---|---|
| Grains per gallon (gpg) | 4.1 | 5.4 | 7.4 |
| German degrees (°dH) | 3.9 | 5.2 | 7.1 |
| French degrees (°f) | 7.0 | 9.3 | 12.6 |
| Clark degrees (°e) | 4.9 | 6.5 | 8.8 |
| mmol/L | 0.70 | 0.93 | 1.26 |
For a dishwasher that asks for German degrees, 7 °dH (the high figure) is a sensible setting. Most dishwasher manuals group values into levels, so look up which level covers 7 °dH in yours.
Do you need a water softener in Austin?
Many Austin homes don’t. At 5.4 gpg on average, you’ll get some white marks on fixtures and a light crust in the kettle, but nothing like the scale in Las Vegas or San Antonio. The USGS describes hardness as a nuisance rather than a health concern.
A softener makes more sense if you have a tankless water heater (whose manual may set a hardness limit), if you dislike spotted glassware and soap scum, or if you live outside Austin Water’s service area on a different supply. Our do I need a water softener checklist helps you weigh it up. If you only fight scale in the kettle and shower, descaling a few times a year is usually enough: see how to remove limescale and how to descale a kettle.
Softener size and salt use in Austin
If you do soften, Austin’s water is light work for even the smallest units. At 7.4 gpg and 80 gallons per person per day:
| People | Grains per week | Size at medium salt | Salt per year | 40 lb bags per year | Salt cost per year |
|---|---|---|---|---|---|
| 1 | 4,144 | 24,000 | 65 lb | 1.6 | $14 |
| 2 | 8,288 | 24,000 | 129 lb | 3.2 | $28 |
| 3 | 12,432 | 24,000 | 194 lb | 4.8 | $42 |
| 4 | 16,576 | 24,000 | 258 lb | 6.5 | $57 |
| 5 | 20,720 | 32,000 | 323 lb | 8.1 | $71 |
| 6 | 24,864 | 32,000 | 387 lb | 9.7 | $85 |
Even a family of four would barely use a 24,000-grain softener: it would go 8 to 10 days between regenerations, depending on the salt setting. If your valve has a maximum-days setting, use it so the resin isn’t left idle for weeks. Try your own numbers here:
This calculator needs JavaScript. The table above covers 1 to 6 people.
Suburbs and other utilities
Austin Water serves the City of Austin and some surrounding areas, but not the whole metro. Round Rock, Pflugerville, Cedar Park, Georgetown and others have their own utilities and their own reports, and some draw on different sources. Check the name on your water bill and use that utility’s report, or test your tap, before setting a softener. Our water hardness lookup only lists figures we have checked in the utility’s own document, and water hardness by city compares them.
Frequently asked questions
Is Austin water hard?
Moderately. The 2025 average of 93 ppm is in the USGS “moderately hard” band, and the highest reading, 126 ppm, is just over the line into “hard”.
What should I set my water softener to in Austin?
About 7.4 gpg, the top of Austin Water’s 2025 range. Our hardness setting guide explains why the high figure is the safer choice.
Does Austin soften its water?
Yes. All three Austin Water treatment plants use lime softening, according to the 2023 external review published by the City of Austin.
Why do I still get limescale in Austin?
Softened at the plant doesn’t mean soft. 5.4 gpg still leaves scale where water is heated or evaporates, just more slowly than in harder cities.
Where can I find Austin’s water quality report?
On Austin Water’s water quality reports page, which links the latest Consumer Confidence Report in English and Spanish.
Sources
- Austin Water: Water quality reports (2025 report: total hardness 70–126 ppm, average 93 ppm)
- Austin Water: Facilities (source lakes and treatment plants)
- City of Austin: External review of Austin Water quality events (2023, PDF)
- USGS Water Science School: Hardness of Water
- PNNL Building America Solution Center: Water Softeners (NSF/ANSI 44 efficiency rating)
