You almost certainly have hard water if you see white crust on faucets and showerheads, spots on dishes and glasses straight out of the dishwasher, soap that will not lather, dry itchy skin and dull hair after a shower, and a shower door that goes cloudy days after you clean it. The number that settles it is 7 grains per gallon (gpg): water at or above 7 gpg is "hard" on the USGS scale, and nearly every tap in eastern Iowa and the Illinois Quad Cities runs above it. Davenport and Bettendorf test at 7.9 to 20.4 gpg, Clinton at about 15, DeWitt at about 13, Fulton at about 18.
Here is what each sign is telling you, how to put a real number on your water for a few dollars or for free, and, just as important, when the fix is not a softener at all.
The five signs of hard water, and what each one means
White crust on faucets, aerators and showerheads. That chalky buildup is calcium carbonate scale, the minerals left behind when water evaporates. It forms fastest on the hot-water side because heat drives minerals out of solution. If you soak your showerhead in vinegar every few months, that is hardness.
Spots and film on dishes and glassware. Rinse aid hides spotting; it does not fix it. If glasses come out hazy even with rinse aid, or the haze no longer washes off, the glass is being etched, and that is permanent.
Soap that will not lather, and a ring in the tub. Calcium and magnesium bind with soap to form a sticky curd. That curd is the bathtub ring, the film on shower tile, and the reason you use more shampoo and detergent than the label says.
Dry, itchy skin and dull hair. The same soap curd leaves a film on you. Skin feels tight after a shower, hair feels waxy or flat, and both are worst in an Iowa winter when indoor air is already dry.
A cloudy shower door. Scale on glass. Squeegeeing helps, but on water in the 13-gpg range the spots are back within days.
There is a sixth sign you cannot see: scale inside the water heater. On unsoftened water a tank heater builds a layer of mineral sediment that insulates the burner from the water, and a tankless heat exchanger scales faster still. A water heater that dies at eight or nine years instead of twelve is the expensive version of the crusted faucet.
What hard water actually is (calcium, magnesium and grains per gallon)
Hardness is dissolved calcium and magnesium. Rain picks it up soaking through limestone and dolomite, which is exactly what eastern Iowa is made of: Silurian dolomite bedrock just below the topsoil, deeper Jordan sandstone that the city wells reach, and a Mississippi River that drains all of it.
Utilities report hardness in milligrams per liter (mg/L) as calcium carbonate; treatment dealers talk in grains per gallon. To convert, divide mg/L by 17.1. The USGS scale everyone uses:
- Soft: 0-60 mg/L (0-3.5 gpg)
- Moderately hard: 61-120 mg/L (3.5-7 gpg)
- Hard: 121-180 mg/L (7-10.5 gpg)
- Very hard: above 180 mg/L (above 10.5 gpg)
Most households start noticing symptoms around 7 gpg. By 10 gpg the signs above are obvious, and by 15 to 20 gpg, where much of this region sits, appliances pay the price.
Is Iowa water hard or soft? The numbers by town
Hard to very hard, and almost none of it is softened before it reaches you. Every figure below comes from the utility's own report or from Iowa DNR or Illinois EPA sampling, converted at 17.1 mg/L per grain.
Davenport, Bettendorf, LeClaire and Riverdale (Iowa American Water, Quad Cities district). The utility's typical water quality sheet lists total hardness of 136-350 mg/L, or 7.9-20.4 gpg, and its 2017 report gave a typical 235 mg/L, about 13.7 gpg. This is Mississippi River water treated by coagulation, carbon filtration, UV and chloramine; the published process has no softening step, and the wide range is the river's seasonal swing passing straight through to your tap. Our Davenport page covers what that means house by house, from the pre-1940 stock on the bluff to the new builds north of 53rd Street.
Clinton and Low Moor (Iowa American Water, Clinton district). 260 mg/L, or 15.2 gpg, with a range of 13.8-18.3 gpg, from seven deep Jordan-aquifer wells (2017 report, the last year hardness was printed). Not softened.
DeWitt (city wells). The city's annual report does not print a hardness line. Iowa DNR raw-water samples of the city's Jordan wells run roughly 220-240 mg/L, about 13 gpg, and the city treats with chlorination only.
Eldridge (city wells). No published figure. The city's Silurian dolomite wells are aerated and filtered for iron but not softened. USGS sampling of Silurian-Devonian municipal wells across the region found a median near 15-16 gpg, but that is a regional number, not Eldridge's; treat it as hard to very hard and test.
Fulton, Illinois (city wells). 307 mg/L, about 18 gpg, in an Illinois EPA sample of finished water from April 2024. Not softened.
Rock Island (city river plant). The city does not soften and does not publish a hardness figure. Long-term river sampling suggests roughly 10 gpg, but that is an estimate; get the number from a test.
Maquoketa (city wells). A wrinkle. Maquoketa's municipal plant has softened by ion exchange since 2006, though it does not publish a finished hardness value, so a test at the tap is the only way to know what a softener of your own would have left to do. The other in-town question is reverse osmosis for the deep-well radium and sodium, covered below.
Private wells, everywhere outside those systems. Most farm and acreage wells around DeWitt, Grand Mound, Welton and Low Moor are drilled 100-300 feet into Silurian dolomite, and that water is hard to very hard with iron and manganese along for the ride. Grand Mound's municipal Silurian well, a fair proxy, computes to about 310 mg/L (18 gpg) with 1.7 mg/L of iron in Iowa DNR sampling. Deep Jordan farm wells are hard too, with extra sodium and some radium. Wells vary farm to farm, so a per-well test is the only honest number.
How to test water hardness at home
Test strips. A few dollars at any hardware store. Dip, wait, match the color. They read in broad bands, plenty to tell 5 gpg from 15. Check the units: many strips read in ppm, and 250 ppm is about 15 gpg.
The soap-bottle test. Free and reliable as a yes-or-no. Fill a clear bottle a third full of cold tap water, add several drops of pure liquid soap (castile soap works; dish detergent does not, because detergents foam in any water), cap it and shake for ten seconds. Soft water gives a tall head of suds over clear water. Hard water gives a thin skim of suds over cloudy, milky water.
Your utility's annual report. Look for "total hardness" and divide by 17.1. The catch here is that Iowa's report template often omits hardness; DeWitt, Eldridge, Maquoketa and Rock Island do not print one, and Iowa American Water last printed a figure years ago.
Drop-count titration. The field test a water dealer runs at your kitchen sink: a measured sample, a reagent added one drop at a time until the color flips, each drop equal to about one grain per gallon. It is accurate enough to size a softener, and it is what we do during a free in-home water test, alongside iron, TDS, pH and a free-versus-total chlorine split that decides which carbon media your house needs.
A lab, for wells. Hardness is the easy part of well water. Bacteria, nitrate and arsenic need a lab. Clinton County's health department in DeWitt and Scott County's in Davenport both sample private wells for bacteria and nitrate at no charge under Iowa's Grants-to-Counties program, but those panels do not include hardness, so pair them with an in-home test.
Signs you need a water softener, and signs you need something else
Hard water is common enough here that it gets blamed for everything. A quick sort:
- Crust, spots, scum, dry skin, scaled heater: hardness. A properly sized water softener is the fix; that page explains how ion exchange works and how sizing from your grain count keeps salt use down.
- Orange or rust stains in the toilet and tub, yellow laundry, water that turns brown after it sits: iron and manganese, almost always on a well. A softener alone will foul on iron; an iron filter ahead of it is the right order.
- Rotten-egg smell, especially from hot water: hydrogen sulfide from the well, or a reaction inside the water heater. That is an ozone or anode problem, not hardness.
- Pool smell, chemical taste, coffee that tastes off: chlorine or chloramine from the utility. A carbon filter removes it; on Quad Cities chloramine it needs to be catalytic carbon, not plain GAC.
- Bad-tasting drinking water, cloudy ice, worries about nitrate, radium, sodium or lead: a kitchen-tap reverse osmosis system, which treats the water you drink rather than the water you bathe in.
- You already own a softener and the symptoms came back: a salt bridge, exhausted resin or a stuck valve mimics hard water perfectly. Softener repair on any brand costs far less than a new unit.
When not to buy a water softener
An honest list, because a softener is a real expense and not always the answer.
Your water tests under about 3.5 gpg. Rare in this region, but if a strip or a titration reads soft, do not let anyone sell you a softener for hardness you do not have.
You rent, or you are moving within a year. A whole-house softener is a plumbing modification. Ask the landlord, or put an under-sink RO on the kitchen tap instead.
Your existing softener just needs attention. Break the salt bridge, check the bypass valve, confirm it is regenerating. Many "my water is hard again" calls end with a repair, not a replacement.
You are on a sodium-restricted diet. A softener swaps calcium and magnesium for sodium, more of it the harder the water, and DeWitt's deep-well water already carries 110-120 ppm of sodium naturally. Softening is still fine for bathing and appliances, but plan on RO for drinking water or potassium chloride for regeneration, and talk to your doctor.
You are rural on septic. A softener is still right for 18-gpg well water, but choose a demand-initiated unit that regenerates on actual use, and on the Illinois side, check the private sewage code on where backwash may discharge before the install.
Get the real number for your house
Midwest Water Solutions is based just east of DeWitt and tests water free in your home across Clinton, Jackson and Scott counties and the Illinois side of the Quad Cities. Carson brings five years of hands-on water-conditioning experience and a conservation degree to every test, the company is insured, and we sell, install and service all brands of softeners, reverse osmosis and filter systems, so the recommendation follows your water, not a product line.
Tests and installs are scheduled Monday through Friday, 8am to 5pm. If you want the grain count for your tap and a straight answer about whether it justifies a softener, call (563) 221-9009 or request a free estimate.