Total dissolved solids is the number that governs a reverse osmosis system, and in the Cedar Valley it starts high. Neither Waterloo Water Works nor Cedar Falls Utilities softens, and USGS sampling of Black Hawk County wells since 1990 shows a median hardness of 271 mg/L. Kind Water Co installs RO here for $800 tank or $900 tankless, fully installed.
Two measurements get used interchangeably here, and shouldn't. Hardness counts calcium and magnesium. TDS counts everything dissolved, hardness included. A membrane doesn't sort minerals by name — it separates water from whatever is dissolved in it — so TDS is the closer proxy for how hard it works, while hardness tells you whether the rest of the house needs help.
| Measurement | What it counts | What the number means here | How it's measured |
|---|---|---|---|
| Total dissolved solids (TDS), mg/L | Everything dissolved in the water, minerals included | The closest stand-in for the load a membrane must separate out. Unsoftened Cedar Valley water arrives with its minerals still in it. | A conductivity meter at the tap; we bring one |
| Hardness, mg/L | Calcium and magnesium only | USGS bands: soft under 60, hard 121–180, very hard above 180. USGS sampling of Black Hawk County wells since 1990 has a median of 271 mg/L, range 177–456. | A titration kit, part of our free in-home test |
| Grains per gallon (gpg) | The same hardness, in the unit softeners are programmed in | 1 gpg equals 17.1 mg/L, so that median lands near 16 gpg. Softener dials use this unit; lab reports use the other. | Same test, converted |
| Iron and manganese, mg/L | Two metals measured separately from hardness | EPA's secondary (aesthetic) standards are 0.3 mg/L iron and 0.05 mg/L manganese. The staining and prefilter questions, especially on a well. | Field test at your sink, or a county lab panel |
Notice what that hardness row does not give you: a figure for your address. The median sits inside a 177–456 range across a county of wells — wide enough that two Cedar Valley homes can honestly need different equipment. So we measure rather than quote a county number back at you. More in our notes on TDS in Iowa water.
Cedar Falls Utilities draws from eight well sites in the Silurian-Devonian aquifer and adds only chlorine and fluoride. Waterloo Water Works runs 13 wells. Neither softens — unusual here, and why the numbers above start where they do. Full picture on our Waterloo and Cedar Falls water treatment page. For an RO buyer the consequence is short: the first device in the chain that touches dissolved minerals is the one you install.
An RO system is a stack, not a single part, and the membrane is the expensive piece at the end. Ahead of it sit sediment and carbon prefilters whose whole job is catching grit and stripping chlorine before either reaches the membrane. Chlorine is hard on membrane material, and Cedar Falls Utilities adds it by design, so on city water those front stages earn their keep daily.
That is why the annual visit matters more than the brochure. Change the cheap filters on schedule and the costly one keeps working; skip them and the membrane absorbs damage the prefilters were meant to take. Annual service is $199/yr on a tank-RO home and $249/yr on a tankless one, and it includes all three RO filters, a water test and a full system check — details on our RO service page.
What we will not do is date your membrane by the calendar. Membranes wear by gallons and by what is in those gallons — five people in an unsoftened Waterloo home run a different duty cycle than a couple in a softened town on identical hardware. The standard is worth knowing too: NSF/ANSI 58 is the reverse osmosis standard, and certifying under it requires reducing total dissolved solids by at least 75%. That is a bar the standard sets, not a measurement of your kitchen — which is what a test at your sink is for.
If you will own both a softener and an RO, plumb the softener first and let the RO drink softened water. Less mineral reaches the membrane, and it is the standard order anyway. Buying one thing now? Buy the one that fixes what bothers you — spotted glassware, shower film and scale in the water heater are softener problems; taste and what is dissolved in your drinking water are RO problems. An RO treats one tap and does nothing for the laundry.
On the acreages between the towns the sequence is the same but the front end is bigger: iron and sediment come out first, and iron and sulfur systems get quoted after a free water test rather than priced here. Iowa State University Extension notes nitrate is odorless and tasteless and that reverse osmosis, distillation and anion exchange remove it — one more reason a well conversation starts with a test. See well water treatment.
The tank system is $800. It holds treated water in a small pressurized tank under the sink, needs no electricity, and suits most homes. It does use cabinet space you may be spending elsewhere.
The tankless system is $900. No storage tank, so the cabinet stays open and flow isn't capped at a tank's worth, but it needs an outlet under the sink. Plenty of kitchens don't have a free one — the outlet is switched, or the disposal has it. A garbage-disposal air switch, $300, moves the disposal to a countertop button and frees it. Plainly: the air switch is thin margin, not a money-maker — just what makes a tankless install possible.
One firm rule: on a private well we install the tank system, never tankless. Wells run high in dissolved solids and a tankless unit loses pressure fighting that — the TDS conversation above, as a plumbing decision.
Every figure is all-in — equipment, installation by a licensed plumbing professional, tax and a lifetime parts warranty. Culligan, Kinetico and RainSoft publish no prices at all; we do.
$100 off for military and first responders, and 0% financing is available. Travel is free for the first 50 miles from our Marion shop, then $1 per mile, confirmed before you book so it lands on the quote. Full breakdowns are at reverse osmosis cost in Iowa.
Half a day, usually less. The work is done by licensed local plumbing professionals we vet, schedule, and stand behind — insured and bonded. The unit mounts inside the sink cabinet, a dedicated drinking-water faucet goes in at the deck through an existing sprayer hole or a new one we drill, and the drain line ties in. It is flushed and tested before anyone leaves. Coverage: lifetime parts, five years media, one year labor.
The free in-home test takes about twenty minutes and gives you your own hardness and TDS figures instead of a county median. No obligation, and if the numbers say you need less than you came in for, we say so. Call 319-319-6566, email ryan@kindwaterco.com, or get a number in minutes with our instant quote tool. Kind Water Co is family-owned, founded in 2021 by Ryan Brunton, and headquartered in Marion.
Beyond Waterloo we cover Cedar Falls, down into Benton County, and on toward Cedar Rapids — along with Evansdale, Hudson, Janesville and Denver. Not on the list? We travel. Call 319-319-6566.
An under-sink tank system is $800 installed and a tankless is $900 — equipment, installation by a licensed plumbing professional, tax and a lifetime parts warranty included. Bundled with a softener and whole-home filtration, the package is $2,850. Annual service is $199 a year on a tank home, $249 on a tankless one. Military and first responders take $100 off.
It gives the membrane more dissolved material to separate, since neither Waterloo Water Works nor Cedar Falls Utilities softens. But the bigger variable is maintenance. Sediment and carbon prefilters are what protect the membrane, and they are consumables — changed on schedule during the annual visit, they take the wear the membrane otherwise would.
Neither utility publishes a tap figure, so an honest answer needs a meter at your sink. What is published is hardness from wells: USGS sampling of Black Hawk County since 1990 gives a median of 271 mg/L across a 177 to 456 range. Two homes in the same city can sit far apart in that spread.
Depends which problem bothers you. Reverse osmosis treats one tap, so it does nothing for the shower, the laundry or the water heater — those are softener jobs, and nothing upstream softens here. If only your drinking water bothers you, the $800 RO is a complete purchase and we will say so.
Not from us. On a private well we install the $800 tank system only, because wells run high in dissolved solids and a tankless unit loses pressure fighting that load. Well homes also start further upstream — iron, sediment and bacteria come first, and the Iowa DNR recommends testing private wells yearly.
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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