Hard water in Los Fresnos, TX
Reported by East Rio Hondo WSC · September 2025
- TX typical
- 112 mg/L
- EPA health violations since 2016
- 7
- Softener for 3 people
- 24k grain
- Data
- Utility report
The water in Los Fresnos carries roughly 181 mg/L of dissolved calcium and magnesium, or 10.6 grains per gallon. That is very hard water. The number comes from East Rio Hondo WSC, dated September 2025. Reports for this system disagree, with values from 181 to 278 mg/L.
Los Fresnos sits 69 mg/L above the typical Texas figure of 112. Of the 10 nearest cities we track, 5 have softer water and 5 have harder. The range nearby runs from 149 mg/L in La Feria to 228 in Harlingen.
What 181 mg/L means at home
Scale forms fast here. Kettles and coffee makers need regular descaling, and showerheads clog unless you clean them.
Tank water heaters collect mineral sediment that insulates the water from the burner, so flushing the tank matters more than usual.
Dishes and glass shower doors spot easily. Soap scum and a dull film on hair or laundry are common complaints.
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 181 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 × 10.6 gpg = 2,385 grains a day. A 24,000-grain unit regenerates about every 10 days.
EPA record for Los Fresnos's water system
7 health-based violations since 2016
Serves about 6,009 people from surface water.
- Health-based
- 7
- Monitoring or reporting
- 27
- Open now
- 0
EPA lists City of Los Fresnos as the system serving Los Fresnos. The hardness figure above comes from a different system's report, which TapWaterData uses for Los Fresnos.
| Contaminant or rule | Violations | Period | Status |
|---|---|---|---|
| Surface Water Treatment Rulefiltration and disinfection | 7 | 2016 | 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 Los Fresnos water hard?
Yes. It measures about 181 mg/L (10.6 grains per gallon), which the USGS classes as very hard.
What is the water hardness in Los Fresnos in grains per gallon?
About 10.6 gpg. One grain per gallon equals 17.1 mg/L, so 181 mg/L divided by 17.1 gives 10.6.
What size water softener do I need in Los Fresnos?
For 3 people using 75 gallons each per day, 10.6 gpg works out to about 2,385 grains a day. A 24,000-grain softener covers that with a regeneration about every 10 days.
Has the Los Fresnos water system had EPA violations?
EPA records show 7 health-based violations for City of Los Fresnos since 2016, involving Surface Water Treatment Rule. There were also 27 monitoring or reporting violations, which are about late or missing tests and notices.
Nearby cities
- Brownsville211 mg/LVery hard
- Cameron Park217 mg/LVery hard
- San Benito224 mg/LVery hard
- Port Isabel210 mg/LVery hard
- Harlingen228 mg/LVery hard
- La Feria149 mg/LHard
- Mercedes166 mg/LHard
- Progreso173 mg/LHard
- Mila Doce161 mg/LHard
- Weslaco164 mg/LHard
Hardness data: TapWaterData US Water Hardness (utility report, September 22, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.