How hard is the water in Rockwall, TX?

Tap water hardness
116mg/L
6.8gpg
Moderately hardCounty estimate

County estimate from 536 water samples in Rockwall County · July 2026

TX typical
112 mg/L
EPA health violations since 2016
0
Softener for 3 people
24k grain
Data
County estimate

Water samples from around Rockwall put hardness at about 116 mg/L (6.8 gpg), which would be moderately hard on the USGS scale. Treat this as a rough guide: it is the median of 536 samples taken across Rockwall County, mostly wells and streams, not a test of Rockwall's treated tap water. One more reason for caution: EPA lists Rockwall's water system as using surface water, which is often softer than the wells behind the county figure.

Rockwall on the hardness scale, with nearby cities
060120180240300360+TX typical 112Forney: 92 mg/LForney 92Murphy: 108 mg/LMurphy 108Royse City: 116 mg/LRoyse City 116Fate: 126 mg/LFate 126Lavon: 126 mg/LLavon 126Wylie: 126 mg/LWylie 126Sunnyvale: 140 mg/LSunnyvale 140Garland: 146 mg/LGarland 146Rowlett: 161 mg/LRowlett 161Sachse: 164 mg/LSachse 164Rockwall 116mg/L as calcium carbonate060120180240300360+TX 112Royse City: 116 mg/LRoyse City 116Fate: 126 mg/LFate 126Lavon: 126 mg/LLavon 126Wylie: 126 mg/LWylie 126Rowlett: 161 mg/LRowlett 161Sachse: 164 mg/LSachse 164116 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Rockwall sits close to the typical Texas figure of 112 mg/L. Of the 10 nearest cities we track, 2 have softer water and 7 have harder. The range nearby runs from 92 mg/L in Forney to 164 in Sachse.

What 116 mg/L means at home

You may see faint white spots on glasses and shower doors after the water dries.

Scale builds up slowly. A kettle or coffee maker needs descaling now and then, maybe every few months.

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

Optional. Plenty of households at this level live with it and descale the kettle now and then.

Water softener

Worth a look if spots on glass bother you, or if your tankless water heater manual asks for softer water.

Carbon filter

Improves taste and removes chlorine. It leaves calcium and magnesium in place.

Softener size for Rockwall

3 people × 75 gallons a day × 6.8 gpg = 1,532 grains a day. A 24,000-grain unit regenerates about every 15 days.

Size it for your household

EPA record for Rockwall's water system

City of Rockwall · PWSID TX1990001

No health-based violations since 2016

Serves about 55,250 people from surface water.

Health-based
0
Monitoring or reporting
0
Open now
0

EPA lists this system as serving Rockwall.

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 Rockwall water hard?

Somewhat. It measures about 116 mg/L (6.8 grains per gallon), which the USGS classes as moderately hard.

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

About 6.8 gpg. One grain per gallon equals 17.1 mg/L, so 116 mg/L divided by 17.1 gives 6.8.

What size water softener do I need in Rockwall?

For 3 people using 75 gallons each per day, 6.8 gpg works out to about 1,532 grains a day. A 24,000-grain softener covers that with a regeneration about every 15 days.

Has the Rockwall water system had EPA violations?

EPA records show no health-based violations for City of Rockwall since 2016.

Nearby cities

All 342 cities in Texas

Hardness data: TapWaterData US Water Hardness (county estimate, July 4, 2026), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.