Knoxville draws its water from roughly 2,300 feet below the surface, out of Cambrian-Ordovician sandstone that the city's own report rates as having “insignificant” contamination susceptibility. Water that old and that deep is pristine and mineral-loaded in equal measure, and Knoxville Water Works does not soften it.
| Knoxville at a glance | What the record shows |
|---|---|
| Who supplies the water | Knoxville Water Works, PWSID IA6342036, 8,400 people served (EPA SDWIS); 2024 Census city estimate 7,440 |
| Where it comes from | Three wells 2,225 to 2,290 feet deep in the Cambrian-Ordovician sandstone, better known in Iowa as the Jordan. The city's report rates the aquifer's contamination susceptibility as “insignificant” |
| Softened at the plant | No. EPA SDWIS lists fourteen treatment records — corrosion inhibitor, hypochlorite disinfection, greensand, anthracite and pressure filtration, permanganate, and adsorption for radionuclides — with no softening objective at all |
| Published hardness | None. The Iowa DNR sample database holds no total-hardness result for this system, and the city publishes no figure. We will not estimate one |
Knoxville's report lists sodium at 154 parts per million, and a finished-water sample on 14 March 2025 measured 137 mg/L with a peak of 155. That is among the highest municipal sodium levels anywhere in central Iowa — Ames, for comparison, runs 8.8 mg/L.
The interesting part is where it comes from. In most towns a high sodium reading means the utility runs an ion exchange softener, which swaps calcium for sodium by design. Knoxville does no such thing. This sodium is geological: it comes up the well with the water, out of sandstone that has been under pressure for a very long time. Sodium is not a regulated contaminant, so no limit is printed beside it in any report, and we are not going to imply one exists.
What it does mean practically is that a home softener here is not the thing that addresses sodium — it would add a little more. Reverse osmosis at the kitchen tap is the technology that does, which makes Knoxville a two-part job: soften the house for the minerals, treat the drinking water separately. Our guide to reverse osmosis versus ordinary filters explains the difference.
Hardness is unregulated in drinking water, so it is not a required line in a Consumer Confidence Report, and the Iowa DNR sample database holds no total-hardness result for Knoxville. Deep Jordan sandstone water elsewhere in Iowa runs genuinely hard, and it would be easy to hand you a neighbouring town's figure and call it close enough. We will not, because a softener sized from a borrowed number is a softener sized wrong.
What we can tell you from the record is that Knoxville's plant runs greensand and permanganate, which is the standard combination for iron and manganese, and adsorption for radionuclides — all of it deep-groundwater housekeeping and none of it softening. Whatever hardness the Jordan hands Knoxville arrives at your door.
One line in Knoxville's federal treatment record is easy to skim past: adsorption, with radionuclides as the objective. Utilities do not install and operate a radionuclide adsorption step for decoration. Deep Cambrian-Ordovician sandstone across Iowa carries naturally occurring radium, and a system pulling from 2,225 to 2,290 feet is exactly the kind that has to deal with it.
The important word there is deal with it. Knoxville has the treatment step in place, which is the difference between this town and a system that has the geology but not the equipment. It is worth reading the city's current report yourself for the actual results rather than taking any company's characterisation of them.
What it means for equipment in the house is modest and specific: the city is handling that at the plant, so a Knoxville household is buying a softener for minerals and, if it wants, reverse osmosis for the sodium and for general drinking-water polish. It is not a job where you are being asked to compensate for something the utility is not doing.
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.
Outside the city, rural Marion County homes sit on private wells with no greensand filter, no permanganate and no annual report. 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. On a well we fit a tank RO rather than a tankless unit, because high dissolved solids cost a tankless system its pressure. Start with free well water testing.
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.
Knoxville is a town with no published hardness number at all, which makes a reading at your own tap the only honest basis for sizing anything. We come to you, measure hardness, iron and the rest at your kitchen sink, and leave you the readings and a written quote before you decide, at no charge. Book your free in-home water test.
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No figure is published. Hardness is unregulated, so it is not required in a Consumer Confidence Report, and the Iowa DNR sample database holds no total-hardness result for PWSID IA6342036. We will not borrow a neighbouring town's number, because a softener sized from a borrowed figure is a softener sized wrong. A free in-home test measures your own tap.
No. EPA SDWIS lists fourteen treatment records for Knoxville Water Works — corrosion inhibitor, hypochlorite disinfection, greensand, anthracite and pressure filtration, permanganate, and adsorption for radionuclides — with no softening objective anywhere in the system.
Because of the geology, not the treatment. Knoxville's report lists sodium at 154 parts per million, and a finished-water sample on 14 March 2025 measured 137 mg/L with a peak of 155. It comes up with the water from wells 2,225 to 2,290 feet deep in Cambrian-Ordovician sandstone. Sodium is not a regulated contaminant and no limit is printed beside it.
No — a softener works by ion exchange, which adds a small amount of sodium rather than removing it. Reverse osmosis at the kitchen tap is the technology that addresses sodium in drinking and cooking water. In Knoxville that makes a softener and an RO system two separate jobs rather than one.
A Kind Water Co softener is $2,500 all-in and $2,850 paired with reverse osmosis, including equipment, installation, taxes and a lifetime parts warranty. A standalone RO system is $800 tank or $900 tankless. Softeners use NSF/ANSI 44 certified components and RO systems are certified to NSF/ANSI 58, with 0% financing and $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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