Alabama runs four chemistry zones. Birmingham draws on the Cahaba River and the Lake Purdy reservoir, and Huntsville on the Tennessee River. The Black Belt agricultural band runs karst-aquifer groundwater through Selma, Demopolis, Marengo and Wilcox County corridors. Mobile and the Gulf Coast run on Mobile Area Water and Sewer's Big Creek Lake: soft at the tap, with a heavy Gulf and Mobile Bay salt-aerosol overlay on top.
HOW IT BREAKS DOWNsoft (Mobile, Montgomery); moderately hard (Huntsville, Birmingham); 1 of 5 covered cities publishes no figure
Birmingham protocol does not port east into the Black Belt karst belt. Huntsville municipal protocol ports cleanly from East Tennessee. Mobile chemistry is soft at the tap but the salt-aerosol load on the Gulf and Mobile Bay shoreline requires two-pass wash and monthly visit frequency on year-round occupied coastal residential. Pine pollen wave statewide March-May is the dominant seasonal contaminant. Tropical-summer humidity squeeze on the Gulf Coast operationally heaviest in the South outside the Charleston Lowcountry — alkaline-soap concentration needs to drop 20-30 percent from the inland Alabama baseline.
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.
Alabama spans 3 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 clean enough to be the last thing that touches the glass. Wash with it, rinse with it, squeegee it off, and nothing measurable is left behind when it dries. No distilled rinse, no deionized final pass, no spot-free rinse aid — the mineral load is too low to precipitate anything you would see. The failure mode at this end of the scale is not water chemistry, it is technique: streaks here come from a worn rubber, a dirty edge, or a pass that dried before it was pulled.
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 Alabama the spread runs from Montgomery at 4–115 mg/L to Huntsville at 68–149 mg/L — a difference big enough that the same bottle of cleaner behaves differently in each.
Where Alabama'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 |
|---|---|---|---|---|
| Huntsville | 95 / 18568–149 mg/L | 86 / 10070–117 mg/L | free chlorine | May, Aug, Oct |
| Birmingham | 107 / 18540–156 mg/L | 45 / 10027.5–388 mg/L | free chlorine | Apr, Aug, Oct |
| Mobile | 152 / 18538.3–49.6 mg/L | 92 / 10065–71 mg/L | free chlorine | Mar, Oct, Nov |
| Montgomery | 157 / 1854–115 mg/L | 46 / 100110–281 mg/L | free chlorine | Apr, Sep, Oct |
| Tuscaloosa | not ranked | not ranked | free chlorine | May, Sep, Oct |
This page is about Alabama's water and nothing else. For how cleaning actually works in Alabama across the year — climate, seasonal timing, the local contaminants, the housing stock — see the Alabama 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.