Hard to very hard at the tap in the covered cities that publish: Orlando and St. Petersburg sit in the hard band, Tampa and Jacksonville in the very hard. What sets Florida apart is the salt aerosol.
HOW IT BREAKS DOWNhard (St. Petersburg, Orlando); very hard (Jacksonville, Tampa); 2 of 6 covered cities publish no figure
Florida sits on the Floridan Aquifer, one of the most productive carbonate aquifers in the world. Tampa blends surface water and still publishes very hard; Jacksonville pulls straight from groundwater and publishes a wider range, moderately hard to extremely hard. The cleaning-relevant variable in coastal Florida is not the tap, however. It is the salt aerosol — measurable on every pane within three miles of the Gulf or the Atlantic on a windy day.
Groundwater picks up its mineral load from whatever it sits in. Limestone and dolomite aquifers produce the hardest municipal water in the country; granite produces some of the softest.
Florida spans 4 hardness bands, which means there is no single answer for the whole state — the method changes as you move across it. Both ends are below.
Tap water is still fine for most residential glass, with two exceptions worth knowing. Dark glass shows a faint mineral haze that lighter glass hides, and glass that is hot enough to flash the water off before you pull the squeegee will spot regardless of how soft the supply is. On both, a distilled final rinse costs about a dollar a window and removes the variable entirely. Everywhere else at this level, the water is not what is wrong.
This is the band where the water starts writing on the glass. Wash with tap — the surfactant holds the minerals in suspension while you work, so the wash pass is not the problem — then rinse with distilled and pull that. The rinse is the whole intervention: it replaces the mineral-bearing water sitting on the glass with water that has nothing in it to leave. This single change resolves most of the "I cleaned it and it still looks bad" complaints in this range, and it does not require buying a system.
A distilled rinse stops being an improvement and becomes the method. Tap water left to dry on glass at this concentration deposits a visible film within minutes, and the film is cumulative: each cleaning that ends in tap water adds a layer that the next cleaning has to get through first. Glass on a sprinkler line or under a runoff drip needs a maintenance interval, not just a better wash — the deposit is arriving faster than a cleaning schedule built around dust would predict.
The hardest water in North America — Phoenix, Las Vegas, West Texas, much of the limestone Midwest. At this concentration calcium carbonate precipitates out of any water that touches the glass and dries, so what you are looking at is essentially limestone, growing one molecular layer at a time. Tap water cannot be part of the final pass under any circumstance, including "just a quick rinse." Above roughly 300 mg/L, buying distilled by the gallon stops making economic sense against a DI filter or a pure-water pole system, and a residential owner cleaning their own glass twice a year is usually better served by a service that already owns one.
Hardest first — the order that matters, because the hard end is where the method has to change. Each figure is the named utility's own published number; cities whose utility publishes none are listed after them, without a band. Within Florida the spread runs from Orlando at 129 mg/L to Jacksonville at 120–341 mg/L — a difference big enough that the same bottle of cleaner behaves differently in each.
Where Florida's city pages sit in the national city rankings: hardness rank out of 185 cities whose utility publishes a figure, dissolved-solids rank out of 100, the disinfectant each utility reports, and the months each city's cleaning calendar marks for a wash. Rank 1 is the hardest or most mineral-heavy. 5 of these 6 cities use chloramine.
| CITY | HARDNESS RANK | TDS RANK | DISINFECTANT | WASH IN |
|---|---|---|---|---|
| Jacksonville | 20 / 185120–341 mg/L | 9 / 100153–864 mg/L | free chlorine | Apr |
| Tampa | 31 / 185186 mg/L | not ranked | ozone + chloramine | Mar |
| St. Petersburg | 42 / 185158 mg/L | not ranked | chloramine | Feb |
| Orlando | 75 / 185129 mg/L | not ranked | ozone + chloramine | Mar |
| Hialeah | not ranked | not ranked | chloramine | Feb |
| Miami | not ranked | not ranked | chloramine | Feb |
This page is about Florida's water and nothing else. For how cleaning actually works in Florida across the year — climate, seasonal timing, the local contaminants, the housing stock — see the Florida cleaning guide.
For a figure at your own address rather than your city, the Hard Water Scorer takes a ZIP code. If you run a pure-water system, the TDS diagnostic reads the other end of the same problem.
Each covered city utility's own published figure, taken from its most recent annual water quality report (Consumer Confidence Report) or its water-quality page, read in 2026. A city figure is the one its utility publishes for the service area, as a single number or the range it reports; it is not a reading from any one tap. A state range runs from the lowest to the highest figure published by the utilities we cover in that state, so it brackets those cities rather than describing an average resident. A state where no covered utility publishes a figure shows a planning estimate, labelled as one.
Private wells are outside all of it. A well is whatever the rock under it says, and the only number that describes one is a test of that tap. Have a reading that disagrees with this table? Send it to us — a number that contradicts the table is worth more than one that confirms it.