Florida’s hard water comes straight from the limestone — and your appliances pay

If your Florida water heater died young or your dishwasher leaves a chalky film, blame the limestone. Most of the state’s water comes from limestone aquifers, and it arrives hard to very hard.

How hard is Florida water?

The U.S. Geological Survey classifies hardness by dissolved calcium carbonate: soft up to 60 mg/L, hard at 121–180, and very hard above 180. Florida’s limestone karst — the same geology behind its springs and sinkholes — pushes most public supplies into the hard-to-very-hard range, as the University of Florida’s IFAS extension explains. Among the metros, Jacksonville is the hardest at roughly 260 ppm (very hard), Miami and Tampa sit around 185–190 ppm (hard), and Orlando is gentler at about 130 ppm (moderately hard). Your exact number is on your annual water-quality report.

Where it does the damage

Hardness becomes scale wherever water is heated or sits still.

• Water heaters: scale coats the element and tank floor, so the unit runs longer for the same hot water and gives out before the 12–15 years makers expect.
• Dishwashers: the white film comes first, then clogged spray arms and valves.
• Washers and ice makers: scale narrows valves and lines, weakening fill and flow.

Telling scale from a real fault

This is where money gets wasted. A chalky residue, a rumbling heater, or cloudy glasses are usually maintenance — flush the tank, clean the filter, add a softener — not reasons to replace a unit. A dead thermostat or failed pump is a different story.

OwnWise is built for that fork. Describe the symptom and your model, and it separates hard-water wear from a genuine failure, estimates a fair repair price, and weighs it against the appliance’s age — so you don’t scrap a heater that just needed a flush.