Hard water in Seguin, TX
Reported by Green Valley SUD · January 2025
- TX typical
- 112 mg/L
- EPA health violations since 2016
- 3
- Softener for 3 people
- 24k grain
- Data
- Utility report
Seguin water measures 125 mg/L (7.3 gpg) of hardness, hard by USGS standards. The number comes from Green Valley SUD, dated January 2025. Reports for this system disagree, with values from 94 to 125 mg/L.
At 125 mg/L, Seguin is 13 mg/L above the typical Texas figure of 112. Of the 10 nearest cities we track, 2 have softer water and 8 have harder. The range nearby runs from 85 mg/L in Cibolo to 212 in San Marcos.
What 125 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 125 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 × 7.3 gpg = 1,640 grains a day. A 24,000-grain unit regenerates about every 14 days.
EPA record for Seguin's water system
3 health-based violations since 2016
Serves about 32,736 people from surface water.
- Health-based
- 3
- Monitoring or reporting
- 0
- Open now
- 0
EPA lists City of Seguin as the system serving Seguin. The hardness figure above comes from a different system's report, which TapWaterData uses for Seguin.
| Contaminant or rule | Violations | Period | Status |
|---|---|---|---|
| Total trihalomethanes (TTHM)a disinfection byproduct | 3 | 2016–2024 | Resolved |
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 Seguin water hard?
Yes. It measures about 125 mg/L (7.3 grains per gallon), which the USGS classes as hard.
What is the water hardness in Seguin in grains per gallon?
About 7.3 gpg. One grain per gallon equals 17.1 mg/L, so 125 mg/L divided by 17.1 gives 7.3.
What size water softener do I need in Seguin?
For 3 people using 75 gallons each per day, 7.3 gpg works out to about 1,640 grains a day. A 24,000-grain softener covers that with a regeneration about every 14 days.
Has the Seguin water system had EPA violations?
EPA records show 3 health-based violations for City of Seguin since 2016, involving Total trihalomethanes (TTHM).
Nearby cities
- New Braunfels202 mg/LVery hard
- Cibolo85 mg/LModerately hard
- Schertz176 mg/LHard
- San Marcos212 mg/LVery hard
- Universal City121 mg/LHard
- Selma180 mg/LHard
- Converse179 mg/LHard
- Live Oak180 mg/LHard
- Windcrest180 mg/LHard
- Kirby180 mg/LHard
Hardness data: TapWaterData US Water Hardness (utility report, January 5, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.