Polk City is the hard-water outlier of the Des Moines metro. Every other community reviewed here softens at the plant. Polk City's plant does not — Central Iowa Water Works describes its treatment as an iron filtration removal system, with no softening step named anywhere. What softening reaches your tap arrives in the roughly 400,000 gallons a day the city buys from Des Moines.
| Polk City at a glance | What the record shows |
|---|---|
| Who supplies the water | Polk City water supply, PWSID IA7770050, 6,533 people served (EPA SDWIS). Polk City is a Central Iowa Water Works founding member, and CIWW owns the Polk City Water Treatment Plant while the city operates it (producer record IA7770052) |
| Where it comes from | Three alluvial wells in the Pennsylvanian aquifer averaging 425,000 gallons a day, plus roughly 400,000 gallons a day purchased from Des Moines Water Works. The city's own material calls it “a blend of local groundwater and regional supply” |
| Softened at the plant | Partly, and not by Polk City. CIWW's facilities page describes the local plant as an iron filtration removal system, with an iron treatment lagoon and a 300,000-gallon elevated tank. No softening step is named. The DMWW share of the blend arrives already lime-softened |
| Published hardness | None. Neither Polk City nor CIWW publishes a hardness figure for this system, so there is no sourced number to quote |
This is the most genuinely uncertain water in the metro, and pretending otherwise would be dishonest. Roughly half of what Polk City delivers is raw Pennsylvanian aquifer groundwater treated only for iron. The other half is Des Moines Water Works water that has already been through lime softening. Blend the two and the hardness at your tap lands somewhere between untreated alluvial groundwater and the 8.76 grain DMWW target — and exactly where depends on the ratio on the day.
Nobody publishes that ratio, and nobody publishes the resulting hardness. We will not hand you the Des Moines figure and call it yours, because half your water never went near that plant. This is the town in the metro where a free in-home test is not a marketing device but the only way to get a number at all.
You can read a lot from a treatment list. CIWW describes the Polk City plant as an iron filtration removal system; the city's own materials add an iron treatment lagoon and a 300,000-gallon elevated tank. A utility does not build and run dedicated iron removal, complete with a lagoon for the residuals, unless the source water carries enough iron to require it.
Iron matters inside a house for two ordinary reasons. It is what puts the orange and rust-brown tint in a toilet tank, a shower corner or a load of white towels — our note on orange staining covers what that looks like. And whatever gets past a plant filter lands in softener resin, coating the bed and quietly costing capacity, so a softener sized correctly on paper starts behaving like a smaller one. In Polk City that means any softener should be specified with iron in mind, not hardness alone.
The city also brought a new 1.5 million gallon tower at Polk City Regional Park online in 2026, which adds storage rather than treatment. Storage smooths demand; it does not change chemistry.
Polk City is one of the few places in this metro where a whole-home softener is the likely recommendation rather than the exception. Every price is all-in: equipment, installation, taxes and a lifetime parts warranty.
Annual maintenance is $199 a year for a tank-RO home and $249 for a tankless-RO home. Diagnostic service calls are $199; a known-issue trip is $99 plus the part. Financing is 0%, and military and first responders take $100 off. Ask for the full written breakdown before you schedule anything, or start one at our instant quote.
North and west of Polk City, acreages near Big Creek and Saylorville Lake draw private wells from the same shallow aquifer the city taps, without the iron filtration plant in between. Our well water setup is a dual-tank system at $3,450, or $3,800 with tank RO, plus UV disinfection at $700 and sediment pre-filtration at $500 when the readings call for them. We fit tank RO rather than tankless on a well, because high dissolved solids cost a tankless unit its pressure. Begin with free well water testing.
We are licensed and insured, and our softeners are built from NSF/ANSI 44 certified components and our reverse osmosis systems are certified to NSF/ANSI 58. Installation is by licensed local plumbing professionals we vet, schedule and stand behind. Our pricing is published and all-in, and where a town has no published number we would rather measure yours than borrow a neighbour's.
There is no published hardness figure for Polk City, and half your water was never softened by anyone. That makes testing the only honest way to size a system here. We come to you, measure hardness, iron and the rest at your kitchen sink, and hand you the readings and a written quote before you decide anything, at no charge. Book your free in-home water test.
Ankeny · Johnston · Grimes · Altoona · Des Moines · Polk County
Its own plant does not. Central Iowa Water Works describes the Polk City Water Treatment Plant as an iron filtration removal system, and no softening step is named in any primary source. Polk City also buys roughly 400,000 gallons a day of already-softened Des Moines Water Works water, so what reaches your tap is a blend of softened and unsoftened.
No figure is published. Neither Polk City nor Central Iowa Water Works publishes a hardness number for this system, and because the supply blends unsoftened local groundwater with softened DMWW water, the result sits somewhere between the two and shifts with the ratio. We will not borrow the Des Moines number, since half your water never went through that plant.
Central Iowa Water Works owns the Polk City Water Treatment Plant and the City of Polk City operates it. The city's own published material states this directly. Polk City appears twice in state records: PWSID IA7770050 as the retail system and IA7770052 as the CIWW producer record.
Because the source water carries iron. Three alluvial wells in the Pennsylvanian aquifer averaging 425,000 gallons a day feed an iron filtration removal system with an iron treatment lagoon and a 300,000-gallon elevated tank. Iron that passes a plant filter stains fixtures and fouls softener resin, which is why a softener here should be specified with the iron reading in hand.
A Kind Water Co softener is $2,500 all-in, including equipment, installation, taxes and a lifetime parts warranty, or $2,850 paired with reverse osmosis. The XL build is $2,800, or $3,150 with RO. Softeners use NSF/ANSI 44 certified components and RO systems are certified to NSF/ANSI 58. Financing is 0%, with $100 off for military and first responders.
Every number on this page comes from a public record. Here is where to open each one yourself.
Whole-home water softening, filtration, and reverse-osmosis drinking water — professionally installed and built to last a lifetime.
Serving Marion, Cedar Rapids & surrounding Linn County communities
Kind Water Co is a d/b/a of Zero Cap Investments LLC · 2258 Bison St, Apt B, Marion, IA 52302
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