Hard water in Round Rock, TX
Reported by City of Round Rock · October 2025
- TX typical
- 112 mg/L
- EPA health violations since 2016
- 0
- Softener for 3 people
- 24k grain
- Data
- Utility report
Tap water in Round Rock has about 169 mg/L of hardness, which is 9.9 grains per gallon. On the USGS scale that counts as hard. The number comes from City of Round Rock, dated October 2025.
At 169 mg/L, Round Rock is 57 mg/L above the typical Texas figure of 112. Of the 10 nearest cities we track, 9 have softer water and 1 has harder. The range nearby runs from 63 mg/L in Wells Branch to 178 in Pflugerville.
What 169 mg/L means at home
Expect white crust on faucets and showerheads, plus spots on dishes that come out of the dishwasher.
Kettles collect scale quickly. Water heaters build up sediment at the bottom of the tank, which makes them work harder over time.
Soap and detergent need a little more to lather, and soap scum shows up in the tub.
Hardness is not a health problem, and EPA sets no limit for it. It is a matter of scale and soap.
What to do about it
At 169 mg/L most of the trouble is scale, and only a few things deal with it.
Ion-exchange water softener
The standard whole-house fix. It swaps calcium and magnesium for sodium or potassium and needs salt plus a drain. Size it with the calculator below.
Salt-free conditioner
No salt and no drain line. It changes how minerals form scale instead of removing them, so water still tests hard.
Reverse osmosis or carbon filter
Under-sink reverse osmosis removes minerals from drinking water only. Plain carbon filters improve taste but do not soften.
3 people × 75 gallons a day × 9.9 gpg = 2,221 grains a day. A 24,000-grain unit regenerates about every 10 days.
EPA record for Round Rock's water system
No health-based violations since 2016
Serves about 130,662 people from surface water.
- Health-based
- 0
- Monitoring or reporting
- 0
- Open now
- 0
Health-based means a contaminant above its legal limit or a missed treatment step. Monitoring and reporting violations are late or missing tests and notices. Source: EPA ECHO, 2026Q3 export, violations with periods starting 2016 or later. Full EPA record.
Questions
Is Round Rock water hard?
Yes. It measures about 169 mg/L (9.9 grains per gallon), which the USGS classes as hard.
What is the water hardness in Round Rock in grains per gallon?
About 9.9 gpg. One grain per gallon equals 17.1 mg/L, so 169 mg/L divided by 17.1 gives 9.9.
What size water softener do I need in Round Rock?
For 3 people using 75 gallons each per day, 9.9 gpg works out to about 2,221 grains a day. A 24,000-grain softener covers that with a regeneration about every 10 days.
Has the Round Rock water system had EPA violations?
EPA records show no health-based violations for City of Round Rock since 2016.
Nearby cities
- Brushy Creek74 mg/LModerately hard
- Wells Branch63 mg/LModerately hard
- Pflugerville178 mg/LHard
- Hutto141 mg/LHard
- Cedar Park157 mg/LHard
- Georgetown148 mg/LHard
- Leander162 mg/LHard
- Manor92 mg/LModerately hard
- Taylor160 mg/LHard
- Austin68 mg/LModerately hard
Hardness data: TapWaterData US Water Hardness (utility report, October 13, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.