Johnston may have softer water than the rest of the metro, and nobody publishes the number that would prove it. The 2026 regional report says Saylorville “serves water to residents north of Des Moines,” and Saylorville softens with ultrafiltration and reverse osmosis rather than lime. Johnston is north of Des Moines. That is a genuinely different finished water, unmeasured in public.
| Johnston at a glance | What the record shows |
|---|---|
| Who supplies the water | Johnston Municipal Water Supply, PWSID IA7740011, 24,897 people served (EPA SDWIS); a founding member of Central Iowa Water Works |
| Where it comes from | Purchased surface water from Des Moines Water Works and Central Iowa Water Works. Johnston sits north of Des Moines, which the 2026 regional report assigns to the Saylorville plant on the Des Moines River |
| Softened at the plant | Yes — but by a different method. The 2026 report says Saylorville “utilizes ultra-filtration and reverse osmosis to soften and treat the water,” where Fleur Drive and L.D. McMullen use lime softening |
| Published hardness | None. Johnston publishes no figure, and Des Moines Water Works does not break its 8.76 grain target down by plant, so no sourced number exists for Saylorville water |
Three plants produce the metro's water and they do not all do the same thing. Fleur Drive and L.D. McMullen use lime softening. Saylorville, a 10 million gallon a day plant fed by two radial collector wells on the Des Moines River and now expanding toward 20, uses ultrafiltration and reverse osmosis. Membrane treatment removes dissolved minerals in a way lime softening does not, which means Saylorville water can leave the plant materially softer than the DMWW-wide 8.76 grain target implies.
The 2026 report assigns Johnston's part of the metro to Saylorville by geography, not by name, and DMWW publishes no plant-by-plant hardness. So the honest statement is this: your water may well be softer than a Des Moines or Urbandale household's, and there is no published figure to confirm it. That is not a gap we can fill with a guess. It is a gap a fifteen-minute test closes exactly.
It matters commercially, too. If Johnston water is genuinely soft off the membrane, a whole-house softener may be the wrong purchase here, and we would rather tell you that during the test than after the install. Our comparison of reverse osmosis against ordinary filters explains why membrane treatment behaves so differently.
Johnston's distribution figures in the 2026 report are unusual in a specific way. Total trihalomethanes are the lowest in the metro at 36 µg/L, comfortably under the 80 µg/L maximum contaminant level. Haloacetic acids, though, are among the highest at 24 µg/L with a range of 15 to 45, against a 60 µg/L limit. Chlorine runs at a 0.80 mg/L running annual average, also the lowest in the metro.
Those two disinfection byproduct families track slightly differently — they form from different precursors and respond differently to how long water sits in a system — so a low reading on one and a higher reading on the other is not a contradiction. Both are under their limits. Carbon is the ordinary treatment for both, and it is standard on our whole-home builds; our carbon filtration guide covers the detail.
The report also lists a UCMR5 lithium detection in Johnston at 14 to 33 µg/L in 2025. UCMR5 is an EPA data-gathering programme for unregulated contaminants; lithium has no drinking water standard, so nothing was exceeded. We mention it because it is in the record.
More than anywhere else in this metro, the Johnston answer depends on what the test says. Every price is all-in: equipment, installation, taxes and a lifetime parts warranty.
Maintenance is $199 a year on a tank-RO home and $249 a year on a tankless-RO home. Diagnostic calls are $199; a known-issue trip is $99 plus the part. We offer 0% financing and $100 off for military and first responders. Ask for the full written breakdown before you schedule, or start one with our instant quote.
North of Johnston, out toward Saylorville Lake and beyond the municipal boundary, homes are on private wells with none of this treatment behind them. Our well water system is a dual-tank build 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.
Kind Water Co is licensed and insured, and our systems carry NSF certifications — NSF/ANSI 44 for the softener components, NSF/ANSI 58 for reverse osmosis. Installation is by licensed local plumbing professionals we vet, schedule and stand behind. Pricing is published and all-in, and we would rather test your water and tell you that you need less than you expected.
Johnston is the clearest case in the metro for testing before buying, because the one number that would settle the question is not published anywhere. We come to you, measure hardness, iron and the rest at your kitchen sink, and hand over the readings and a written quote whether you buy or not. Book your free in-home water test.
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Possibly, and no published figure confirms it. The 2026 regional report says the Saylorville plant “serves water to residents north of Des Moines” and that Saylorville uses ultrafiltration and reverse osmosis to soften, rather than the lime softening used at Fleur Drive and L.D. McMullen. Johnston lies north of Des Moines. No plant-by-plant hardness is published.
Nobody publishes a number. Johnston Municipal Water Supply publishes no hardness figure, and Des Moines Water Works states only a system-wide target of less than 150 mg/L, or 8.76 grains per gallon, without breaking it down by plant. Because Johnston may be on membrane-softened Saylorville water, we will not apply the system-wide figure to your house.
The 2026 regional report gives Johnston the metro's lowest trihalomethanes at 36 µg/L against an 80 µg/L limit, and among the highest haloacetic acids at 24 µg/L, range 15 to 45, against a 60 µg/L limit. The two families form from different precursors and behave differently in a distribution system. Both are under their limits.
That depends entirely on your test result, which is an unusual answer for Iowa. If Johnston is receiving membrane-softened Saylorville water, a whole-house softener may be the wrong purchase, and reverse osmosis at the kitchen tap may be the whole job. We would rather establish that during the free test than after an install.
The 2026 regional report lists a UCMR5 lithium detection in Johnston at 14 to 33 µg/L in 2025. UCMR5 is an EPA monitoring programme that collects occurrence data on unregulated contaminants. Lithium has no drinking water standard, so no limit was exceeded. We report it because it appears in the published record.
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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