Hard water in St. Augustine, FL
Reported by Sjcu-Cr214 Mainland WTP · June 2025
- FL typical
- 120 mg/L
- EPA health violations since 2016
- 0
- Softener for 3 people
- 24k grain
- Data
- Utility report
Tap water in St. Augustine has about 211 mg/L of hardness, which is 12.4 grains per gallon. On the USGS scale that counts as very hard. The number comes from Sjcu-Cr214 Mainland WTP, dated June 2025.
At 211 mg/L, St. Augustine is 91 mg/L above the typical Florida figure of 120. Of the 10 nearest cities we track, 9 have softer water and 1 has harder. The range nearby runs from 24 mg/L in Daytona Beach to 234 in Jacksonville Beach.
What 211 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 211 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 × 12.4 gpg = 2,781 grains a day. A 24,000-grain unit regenerates about every 8 days.
EPA record for St. Augustine's water system
No health-based violations since 2016
Serves about 66,953 people from groundwater.
- Health-based
- 0
- Monitoring or reporting
- 10
- Open now
- 0
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 St. Augustine water hard?
Yes. It measures about 211 mg/L (12.4 grains per gallon), which the USGS classes as very hard.
What is the water hardness in St. Augustine in grains per gallon?
About 12.4 gpg. One grain per gallon equals 17.1 mg/L, so 211 mg/L divided by 17.1 gives 12.4.
What size water softener do I need in St. Augustine?
For 3 people using 75 gallons each per day, 12.4 gpg works out to about 2,781 grains a day. A 24,000-grain softener covers that with a regeneration about every 8 days.
Has the St. Augustine water system had EPA violations?
EPA records show no health-based violations for Sjcu-Cr214 Mainland WTP since 2016. There were also 10 monitoring or reporting violations, which are about late or missing tests and notices.
Nearby cities
- Nocatee189 mg/LVery hard
- Palm Valley149 mg/LHard
- Fruit Cove189 mg/LVery hard
- Palm Coast68 mg/LModerately hard
- Jacksonville Beach234 mg/LVery hard
- Atlantic Beach156 mg/LHard
- Bellair-Meadowbrook Terrace189 mg/LVery hard
- Jacksonville189 mg/LVery hard
- Ormond Beach58 mg/LSoft
- Daytona Beach24 mg/LSoft
Hardness data: TapWaterData US Water Hardness (utility report, June 17, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.