Marshalltown is one of the few Iowa cities that both softens its water and says what it softens it to. Marshalltown Water Works states its finished water is “softened to between six to eight grains of hardness,” and the state sample database recorded 115 mg/L — 6.7 grains — at 1 East Main Street. What is more interesting is the step that comes before the softening.
| Marshalltown at a glance | What the record shows |
|---|---|
| Who supplies the water | Marshalltown Water Works, PWSID IA6469042, 27,680 people served (EPA SDWIS); 2024 Census city estimate 27,886 |
| Where it comes from | Municipal wells. The plant treats an average of 6.5 million gallons a day with peaks of 9 to 10 million |
| Softened at the plant | Yes. The utility's 2025 report describes aeration to remove iron, radon and hydrogen sulfide, then a softening basin “for removal of the excess hardness and the remaining iron,” then pH adjustment and sand filtration. EPA SDWIS also records reverse osmosis under the softening objective |
| Published hardness | 115 mg/L as calcium carbonate, or 6.7 grains per gallon, in finished water sampled 05/16/2018 (Iowa DNR Drinking Water Portal, analyte 84); the utility publishes a range of six to eight grains |
Most lime softening plants in Iowa aerate somewhere in the process. Marshalltown puts it at the front and names three targets: iron, radon and hydrogen sulfide. A utility does not design a process train that way unless the raw water genuinely carries all three.
Hydrogen sulfide is the rotten-egg smell that turns up in deep groundwater across the state; our note on that smell covers where it comes from. Radon is a dissolved gas that aeration strips efficiently, which is exactly why it goes first. And iron gets a second pass later, in the softening basin, because aeration alone does not finish the job. That is a well-designed plant dealing with a demanding source, and it is why Marshalltown's finished water arrives at six to eight grains rather than the twenty-plus its raw water would imply.
At 6.7 grains Marshalltown is among the softer municipal supplies in central Iowa — comfortably below Grinnell at 28.7 and even below the Des Moines target of 8.76. On the EPA scale it is still classed as hard, so you will find film on shower glass and spotting on dark dishes, and a water heater still collects scale, just far more slowly than most of Iowa.
Whether a home softener earns its price at 6.7 grains is a genuinely open question and depends on the house. Sodium is low at 18 parts per million and chlorine runs 2.51 ppm, which is a normal working residual and the usual reason people notice a taste. A carbon stage or a reverse osmosis unit handles that; a softener does not. Our note on chlorine taste covers the distinction.
Marshalltown Water Works treats an average of 6.5 million gallons a day and peaks at 9 to 10 million. That is a 50% swing between an ordinary day and a hot July afternoon, and it is the reason finished hardness is published as a range of six to eight grains rather than a single figure.
Plants under peak load have less residence time in every basin, and a lime softening basin is where that shows first — the reaction is chemical and it needs time. So the eight-grain end of the published range is the summer end, and the six-grain end is the rest of the year. Neither is wrong; they are the same plant working at different rates.
Which is a useful thing to know if you are deciding whether a softener is worth it here. Sizing from the six-grain figure alone would leave you short in the months you notice hardness most.
Every price is all-in: equipment, installation, taxes and a lifetime parts warranty.
Annual maintenance is $199 a year on a tank-RO home and $249 a year on a tankless-RO home. A full diagnostic call is $199; a known-issue trip is $99 plus the part. We run 0% financing and take $100 off for military and first responders. Ask for the written breakdown before anything is scheduled, or begin one with our instant quote.
Rural Marshall County homes draw the same groundwater without the aeration tower in front of it, which means the iron, the hydrogen sulfide and the full hardness all arrive at the house. That is a different job from a city install and usually a bigger one. Our well water setup is a dual-tank system at $3,450, or $3,800 with tank RO, with UV disinfection at $700 and sediment pre-filtration at $500 when the readings call for them. Tank RO rather than tankless on a well, because high dissolved solids cost a tankless unit its pressure.
We are licensed and insured, and our systems carry NSF certifications — NSF/ANSI 44 for the softener components, NSF/ANSI 58 for reverse osmosis. Installs are carried out by licensed local plumbing professionals we vet, schedule and stand behind. Prices are published, all-in and the same for every home, so the number on this page is the number you sign.
Marshalltown is a city where the honest answer may well be that you need less equipment than you expected. We come to you, measure hardness, iron, chlorine and the rest at your kitchen sink, and leave the readings and a written quote with you at no charge either way. Book your free in-home water test.
Ames · Newton · Grinnell · Iowa Falls · Des Moines
Marshalltown Water Works states its finished water is “softened to between six to eight grains of hardness,” and the Iowa DNR sample database recorded 115 mg/L as calcium carbonate — 6.7 grains per gallon — in a finished-water sample taken at 1 East Main Street on 16 May 2018.
Yes. The utility's 2025 report describes aeration to remove iron, radon and hydrogen sulfide, then a softening basin “for removal of the excess hardness and the remaining iron,” then pH adjustment and sand filtration. EPA SDWIS also records reverse osmosis under the softening objective for this system.
Because the raw water carries iron, radon and hydrogen sulfide, and aeration strips all three efficiently. Radon in particular is a dissolved gas that comes out readily under aeration, which is why it goes at the front of the process train. Iron gets a second pass later in the softening basin.
It is a genuinely open question at six to eight grains, and it depends on the house. The water is still classed as hard on the EPA scale, so scale keeps forming, just slowly. Sodium is low at 18 parts per million. If chlorine taste is what you have noticed, that is a carbon or reverse osmosis job rather than a softener one.
A standalone Kind Water Co reverse osmosis system is $800 for the tank model and $900 tankless, all-in with equipment, installation, taxes and a lifetime parts warranty. Paired with a softener and a carbon stage the package is $2,850. RO systems are certified to NSF/ANSI 58, with 0% financing and $100 off for military and first responders.
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