St. Petersburg homeowner guide
The City of St. Petersburg’s 2024 Water Quality Report lists average finished-water hardness at 165 mg/L as calcium carbonate. Using the EPA conversion of 17.1 mg/L per grain per gallon, that is about 9.6 gpg. This is a utility average, not a guaranteed reading at every tap.
Official city result
165 mg/Laverage hardness as calcium carbonateHardness measures primarily calcium and magnesium. It is usually an aesthetic and maintenance concern rather than a health-limit score. Around this level, many households notice spotting, soap-use differences or scale on heated surfaces.
St. Petersburg receives a dynamic regional blend of groundwater, surface water and desalinated water. Distribution conditions, supply changes and building plumbing can change a tap reading.
Use 9.6 gpg as context, not final equipment programming. Test the untreated tap at the property and account for iron or other conditions before sizing a system.
| City-reported 2024 average | Converted value | Use |
|---|---|---|
| 165 mg/L as CaCO₃ | About 9.6 gpg | Citywide planning context, not ZIP-level guarantee |
Questions homeowners ask
Hardness is not a drinking-water safety score. Review the complete official report for regulated contaminant results.
That graphic used an unverified third-party example. This site does not publish it because the current official city report gives 165 mg/L.
Confirm the untreated property reading first and follow the equipment manufacturer’s instructions.
A practical next step
Share the property basics and the result you want. An assessment request is not a contract or guaranteed appointment.
