Three distinct urban water profiles: Cleveland on Lake Erie, Columbus on Scioto-and-groundwater, Cincinnati on the Ohio River. Cleveland, Columbus and Akron publish moderately hard water, Cincinnati and Dayton hard. Outstate towns on the limestone belt lean on wells, and winter salt severity runs a north-south gradient.
HOW IT BREAKS DOWNmoderately hard (Columbus, Cleveland, Akron); hard (Dayton, Cincinnati); 1 of 6 covered cities publishes no figure
Ohio is three states for the purposes of this trade. Cleveland and most of northeast Ohio draw from Lake Erie via the Cleveland Division of Water and adjacent municipal systems; hardness sits at a published 105–130 mg/L (moderately hard to hard). Columbus and central Ohio pull from the Scioto River system (Hoover, Griggs, and O'Shaughnessy reservoirs) blended with limestone-aquifer well augmentation, with Columbus at a published 120 mg/L (moderately hard). Cincinnati on the Ohio River (the Greater Cincinnati Water Works draws at the California intake) sits at a published 126–140 mg/L (hard), and Dayton on its buried-valley aquifer at a published 155 mg/L (hard). Toledo on Lake Erie publishes no figure the site uses. Akron blends surface and groundwater at a published 76–150 mg/L. The outstate housing stock is on private wells drawn from sandstone and limestone aquifers that no utility reports, with iron staining a comparable secondary issue.
A blended system means hardness moves with the blend. Two addresses on the same utility can read differently, and the same address can read differently across a year, depending on which source is carrying the load that season.
Ohio spans 2 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.
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 Ohio the spread runs from Akron at 76–150 mg/L to Dayton at 155 mg/L — a difference big enough that the same bottle of cleaner behaves differently in each.
Where Ohio'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.
| CITY | HARDNESS RANK | TDS RANK | DISINFECTANT | WASH IN |
|---|---|---|---|---|
| Dayton | 44 / 185155 mg/L | not ranked | free chlorine | Aug, Oct |
| Cincinnati | 69 / 185126–140 mg/L | not ranked | free chlorine | Aug, Oct |
| Columbus | 87 / 185120 mg/L | not ranked | uv + chlorine | Aug, Oct |
| Cleveland | 92 / 185105–130 mg/L | 51 / 100180 mg/L | free chlorine | Jun |
| Akron | 98 / 18576–150 mg/L | not ranked | free chlorine | Aug, Oct |
| Toledo | not ranked | not ranked | free chlorine | Jul, Oct |
This page is about Ohio's water and nothing else. For how cleaning actually works in Ohio across the year — climate, seasonal timing, the local contaminants, the housing stock — see the Ohio 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.