Hard water in Sonterra, TX

Tap water hardness

147mg/L

8.6gpg

HardReports range 90–147

Reported by Sonterra MUD · June 2022

TX typical: 112 mg/L
EPA health violations since 2016: 2
Softener for 3 people: 24k grain
Data: Utility report

The water in Sonterra carries roughly 147 mg/L of dissolved calcium and magnesium, or 8.6 grains per gallon. That is hard water. The number comes from Sonterra MUD, dated June 2022. Reports for this system disagree, with values from 90 to 147 mg/L.

Sonterra on the hardness scale, with nearby cities

Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

At 147 mg/L, Sonterra is 35 mg/L above the typical Texas figure of 112. Of the 10 nearest cities we track, 4 have softer water and 6 have harder. The range nearby runs from 74 mg/L in Brushy Creek to 285 in Harker Heights.

What 147 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 147 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.

Softener size for Sonterra

3 people × 75 gallons a day × 8.6 gpg = 1,935 grains a day. A 24,000-grain unit regenerates about every 12 days.

Size it for your household

EPA record for Sonterra's water system

Sonterra MUD · PWSID TX2460157

2 health-based violations since 2016

Serves about 16,614 people from surface water.

Health-based: 2
Monitoring or reporting: 7
Open now: 0

Each dot is one health-based violation, placed at the start of its compliance period.

Contaminant or rule	Violations	Period	Status
Fluoride	2	2017	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 Sonterra water hard?

Yes. It measures about 147 mg/L (8.6 grains per gallon), which the USGS classes as hard.

What is the water hardness in Sonterra in grains per gallon?

About 8.6 gpg. One grain per gallon equals 17.1 mg/L, so 147 mg/L divided by 17.1 gives 8.6.

What size water softener do I need in Sonterra?

For 3 people using 75 gallons each per day, 8.6 gpg works out to about 1,935 grains a day. A 24,000-grain softener covers that with a regeneration about every 12 days.

Has the Sonterra water system had EPA violations?

EPA records show 2 health-based violations for Sonterra MUD since 2016, involving Fluoride. There were also 7 monitoring or reporting violations, which are about late or missing tests and notices.

Nearby cities

All 342 cities in Texas

Hardness data: TapWaterData US Water Hardness (utility report, June 16, 2022), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.