Arsenic is a natural element in the rock and soil under Iowa, and some of it ends up in well water. It is more common in some parts of the state than others, and the only way to know about your own well is a lab test. The good news: the county test is free for Iowa well owners, the result is easy to read once you know the units, and there are simple ways to treat it if your number comes back high. Here is what to know, in order.
Between 2014 and 2024, Iowa's Private Well Grants program tested 22,133 different wells for arsenic. IIHR, a University of Iowa research institute and one of the two partners in the Iowa INSIGHT program, found that about 11% were over the 10 µg/L federal limit and another 8.4% fell between 5 and 10 µg/L.
Where you live matters. IIHR reports the highest rates in north-central Iowa, in Cerro Gordo, Franklin, Hardin, Hamilton, Hancock, Kossuth and Calhoun counties, and it lists Dubuque, Buchanan, Woodbury and Monona counties among the places that frequently report results over the limit. The arsenic comes from the geology under each county, so a neighbor's result is a hint, not an answer.
This is not new. An earlier statewide study, the University of Iowa's 2006 to 2008 survey of 473 rural wells in 89 counties, found arsenic in 48% of the samples and 8% at or above the limit.
Iowa's Private Well Grants Program provides free testing for bacteria, nitrate, arsenic and manganese to private well owners, arranged through your county environmental health office. The Iowa DNR lists arsenic and manganese as covered every three years. Here is how to request your county test.
A standard lab result is total arsenic, all forms added together. Labs print it in different units, so check yours: 0.010 mg/L, 10 µg/L and 10 ppb are the same amount, and each one equals the legal limit for public water (Iowa DNR). On an IIHR kit, "not detected" means below 0.2 µg/L, the smallest amount its lab method can measure.
Arsenic comes in two main forms, arsenite (arsenic III) and arsenate (arsenic V). The form decides how easily it comes out of water and which treatment works best, and the State Hygienic Laboratory offers a separate speciation test to sort it out. In the 2006 to 2008 survey's speciation work, arsenite made up as much as 75% of the total arsenic in the samples tested.
IIHR groups results into four bands. This table puts its guidance and its retest timing side by side.
| Your result | What IIHR says | When to test again |
|---|---|---|
| Not detected (under 0.2 µg/L) | Meets all current drinking water standards for arsenic. | At least once every three years |
| Detected, under 5 µg/L | Present at a low level. IIHR says this range is "less likely to cause health concerns." | At least once every three years |
| 5 to 10 µg/L | Below the federal limit but "of concern." New Jersey and New Hampshire set their limits at 5 µg/L. IIHR recommends treatment, rural water or bottled water for drinking and cooking. | More often than every three years. With treatment: retest to confirm it works, then at least once a year. |
| Over 10 µg/L | Over the federal limit. IIHR recommends you stop drinking the water and use treatment, rural water or bottled water for drinking and cooking. | Retest after treatment is installed to confirm it works, then at least once a year. |
The EPA's own health goal for arsenic is zero, which is why IIHR treats the 5 to 10 band as worth acting on. Whatever your number, IIHR says you can keep washing dishes and showering: very little arsenic stays on dishware, and very little is absorbed through the skin. Its advice is about the water you drink and cook with. If your water ever looks cloudy or colored, IIHR advises not drinking or cooking with it, because the particles can concentrate arsenic.
Iowa agencies word this differently. The Iowa DNR says every private well should have at least one arsenic test and should be tested more often if an earlier test found contamination, and its free program covers arsenic every three years. The State Hygienic Laboratory says to test arsenic at least once in the life of the well. IIHR ties the timing to your result. We follow IIHR's version, because it fits inside all of the others:
Arsenic levels in groundwater are fairly stable, so any time of year works for the test (Iowa DNR).
If your home is on city or rural water, your utility tests for arsenic and must meet the 10 µg/L limit. The Iowa DNR says private individuals do not need to test for arsenic when their water comes from a public water system, and public suppliers must notify customers when a standard is exceeded.
Arsenic does show up in city water at low levels. It appears on 46 of our free Iowa city water reports, and every one of those results is under 5 ppb; the highest is 4.67 ppb. The "x" number beside each result compares it to a health-based guideline of 0.004 ppb, the same figure as California's public health goal for arsenic, not to the 10 ppb legal limit. Our Colfax report, for example, shows 0.7 ppb. That is 175 times the guideline and well under the legal limit. It is not a violation; it shows how far a result sits above the strictest health goal.
The State Hygienic Laboratory lists distillation, reverse osmosis, activated alumina and anionic resin. For a well over 10 µg/L, IIHR says a reverse osmosis filter at a drinking water tap is "usually the most practical and affordable solution." It adds two cautions. Iron and manganese can plug an RO filter, so some homes need those removed first. And some water needs a pre-treatment step to change the arsenic into a form RO removes more readily. That is why the rest of your test, and the form of arsenic, matter. Where a rural water system serves your road, IIHR also lists connecting to it as an option.
Our under-sink reverse osmosis systems are $897 for the tank model and $997 tankless, installed, with tax included. On a well we fit the tank model, because high dissolved solids cost a tankless unit its pressure. Both are certified to NSF/ANSI 58 for total dissolved solids reduction. That certification does not list arsenic, so we don't quote an arsenic number for them. Have the treated tap lab-tested after installation, as IIHR recommends.
For homes on private wells, Kind Water Co also installs a whole-home arsenic tank, installed after the softener and priced by quote.
IIHR's advice for any home that installs arsenic treatment is the same: retest to confirm it is working, then at least once a year while you rely on it. If you used an IIHR kit, you can request a follow-up kit after installing treatment; the details are on IIHR's arsenic page. Homes that already have treatment are sent two kits, one for the untreated well water and one for the treated tap, according to The Daily Iowan. Testing both shows exactly what the system is doing.
On September 15, 2026, the University of Iowa's Iowa INSIGHT program began offering free at-home arsenic test kits to eligible private well owners in Benton, Cedar, Floyd, Jones, Mitchell and Plymouth counties. IIHR chose them because few of their wells have arsenic results and they border areas where tests often come back high. The program had 300 requests in its first two weeks, The Daily Iowan reported. You can request a kit on IIHR's arsenic page.
Across Iowa, your county environmental health office arranges the free Private Well Grants test. Numbers we checked on October 22, 2026:
| County | Office | Phone | Good to know |
|---|---|---|---|
| Polk | Polk County Environmental Health Services | 515-286-3705 | Free well test for bacteria, E. coli, nitrate, arsenic and manganese. Request it through the county's online permit portal. |
| Benton | Benton County Environmental Health, Vinton | 319-472-3119 | Free well test. INSIGHT kit county. |
| Cedar | Cedar County Environmental Health | 563-886-2248 | Tests arsenic and manganese every three years. INSIGHT kit county. |
| Floyd | Floyd County Environmental Health, Charles City | 641-257-6145 | Free private well test. INSIGHT kit county. |
| Jones | Jones County Environmental Health, Anamosa | 319-462-4715 | Free once a year when grant funds allow. INSIGHT kit county. |
| Mitchell | Mitchell County Environmental Health, Osage | 641-832-3943 | Well water testing. INSIGHT kit county. |
| Plymouth | Plymouth County Sanitarian, Le Mars | 712-546-1259 | No fee for testing. Its page also links the free arsenic kit. |
For Linn, Johnson, Black Hawk and Dubuque counties, see our free well testing guide. For every other county, the Iowa DNR's Private Well Program page links each county health department.
Kind Water Co is a family-owned Iowa company, founded in 2021 by Ryan Brunton, with its head office in Des Moines. Our free in-home water test measures hardness, iron and total dissolved solids and gives a nitrate screening reading at your kitchen sink. It does not test arsenic. That takes a certified lab, and for well owners the county test is free.
Ready when you are: request a free in-home water test or get a 60-second instant quote.
Between 2014 and 2024, Iowa's Private Well Grants program tested 22,133 wells for arsenic. About 11% were over the 10 µg/L federal limit and another 8.4% were between 5 and 10 µg/L, according to the University of Iowa's IIHR. The highest rates are in north-central Iowa.
It depends on your last result. If arsenic was not detected or was under 5 µg/L, test at least once every three years, which is what Iowa's free county program covers. From 5 to 10 µg/L, test more often. Over 10 µg/L, or once you install treatment, retest to confirm it works and then at least once a year. That is the University of Iowa IIHR's schedule.
No. The Minnesota Department of Health says conventional water softeners and activated carbon filters alone will not remove arsenic, and IIHR says pitcher filters and whole-house carbon filters do not remove it either. The State Hygienic Laboratory lists distillation, reverse osmosis, activated alumina and anionic resin as the methods that do.
No. The State Hygienic Laboratory says arsenic cannot be removed from water by boiling, and the Minnesota Department of Health notes that boiling concentrates arsenic as some of the water evaporates.
Yes, according to IIHR. You can keep washing dishes, because the arsenic left on dishware is very low, and you can keep bathing and showering, because arsenic is minimally absorbed through the skin. Its advice is about the water you drink and cook with.
No. Our free in-home water test measures hardness, iron and total dissolved solids and gives a nitrate screening reading. Arsenic needs a certified lab, and private well owners in Iowa can get that test free through their county environmental health office.
Arsenic is a health topic, so every number on this page links to the agency or study it came from. We read each one on October 22, 2026.
Whole-home water softening, filtration, and reverse-osmosis drinking water — professionally installed and built to last a lifetime.
Serving Des Moines, Polk County & homes across Iowa
Kind Water Co is a d/b/a of Zero Cap Investments LLC · 600 SE 15th St, Des Moines, IA 50317
.webp)
