Hard water in Largo, FL
Reported by Pinellas County Utilities · October 2025
- FL typical
- 120 mg/L
- EPA health violations since 2016
- 0
- Softener for 3 people
- 24k grain
- Data
- Utility report
Largo water measures 133 mg/L (7.8 gpg) of hardness, hard by USGS standards. The number comes from Pinellas County Utilities, dated October 2025.
At 133 mg/L, Largo is 13 mg/L above the typical Florida figure of 120. Of the 10 nearest cities we track, 3 have softer water and 1 has harder. The range nearby runs from 129 mg/L in West Lealman to 144 in Clearwater.
What 133 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 133 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 × 7.8 gpg = 1,750 grains a day. A 24,000-grain unit regenerates about every 13 days.
EPA record for Largo's water system
No health-based violations since 2016
Serves about 506,353 people from surface water.
- Health-based
- 0
- Monitoring or reporting
- 18
- 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 Largo water hard?
Yes. It measures about 133 mg/L (7.8 grains per gallon), which the USGS classes as hard.
What is the water hardness in Largo in grains per gallon?
About 7.8 gpg. One grain per gallon equals 17.1 mg/L, so 133 mg/L divided by 17.1 gives 7.8.
What size water softener do I need in Largo?
For 3 people using 75 gallons each per day, 7.8 gpg works out to about 1,750 grains a day. A 24,000-grain softener covers that with a regeneration about every 13 days.
Has the Largo water system had EPA violations?
EPA records show no health-based violations for Pinellas County Utilities since 2016. There were also 18 monitoring or reporting violations, which are about late or missing tests and notices.
Nearby cities
- Bardmoor133 mg/LHard
- Seminole133 mg/LHard
- Clearwater144 mg/LHard
- Pinellas Park133 mg/LHard
- West Lealman129 mg/LHard
- Safety Harbor133 mg/LHard
- Lealman129 mg/LHard
- Dunedin130 mg/LHard
- Treasure Island133 mg/LHard
- South Pasadena133 mg/LHard
Hardness data: TapWaterData US Water Hardness (utility report, October 1, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.