Hard water in San Juan, TX
Reported by North Alamo WSC · June 2022
- TX typical
- 112 mg/L
- EPA health violations since 2016
- 0
- Softener for 3 people
- 24k grain
- Data
- Utility report
The water in San Juan carries roughly 162 mg/L of dissolved calcium and magnesium, or 9.5 grains per gallon. That is hard water. The number comes from North Alamo WSC, dated June 2022. Reports for this system disagree, with values from 162 to 228 mg/L.
San Juan sits 50 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 156 mg/L in Edinburg to 216 in Donna.
What 162 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 162 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 × 9.5 gpg = 2,131 grains a day. A 24,000-grain unit regenerates about every 11 days.
EPA record for San Juan's water system
No health-based violations since 2016
Serves about 30,000 people from surface water.
- Health-based
- 0
- Monitoring or reporting
- 5
- Open now
- 0
EPA lists City of San Juan as the system serving San Juan. The hardness figure above comes from a different system's report, which TapWaterData uses for San Juan.
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 San Juan water hard?
Yes. It measures about 162 mg/L (9.5 grains per gallon), which the USGS classes as hard.
What is the water hardness in San Juan in grains per gallon?
About 9.5 gpg. One grain per gallon equals 17.1 mg/L, so 162 mg/L divided by 17.1 gives 9.5.
What size water softener do I need in San Juan?
For 3 people using 75 gallons each per day, 9.5 gpg works out to about 2,131 grains a day. A 24,000-grain softener covers that with a regeneration about every 11 days.
Has the San Juan water system had EPA violations?
EPA records show no health-based violations for City of San Juan since 2016. There were also 5 monitoring or reporting violations, which are about late or missing tests and notices.
Nearby cities
- Alamo166 mg/LHard
- Pharr210 mg/LVery hard
- Murillo161 mg/LHard
- McAllen211 mg/LVery hard
- Donna216 mg/LVery hard
- Hidalgo161 mg/LHard
- Edinburg156 mg/LHard
- Olivarez161 mg/LHard
- Weslaco164 mg/LHard
- Mission177 mg/LHard
Hardness data: TapWaterData US Water Hardness (utility report, June 30, 2022), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.