Iowa Private Well Water Quality 2026

Iowa’s Nitrate Crisis — and Why Well Owners Are Most at Risk

Iowa is one of the most agriculturally intensive states in the country, and that shows in its groundwater. Fertiliser and livestock manure nitrogen leach through Iowa’s soil and tile drainage systems year-round, contaminating both surface water and the shallow aquifers that feed private wells. For municipal water users, nitrate removal systems stand between the contamination and the tap. For private well owners, there is no such buffer — what’s in the aquifer is what’s in the glass.

Iowa’s own health tracking data shows that 12% of tested private wells exceed the federal nitrate limit of 10 mg/L — and that figure comes only from wells that have actually been tested. Research by the Iowa Environmental Council found that over 70% of Iowa households with private wells had not tested their water in the previous year. An estimated 76,000 Iowans are drinking well water straight from the tap with no knowledge of whether it’s safe.

Nitrate is colourless and tasteless. It poses an acute danger to infants under six months — causing a potentially fatal condition called methemoglobinemia, or blue baby syndrome — and longer-term exposure has been linked by researchers to elevated cancer risk. Iowa has the second-highest cancer rate in the nation, and researchers at the Harkin Institute at Drake University and the Iowa Environmental Council have launched an initiative specifically studying the relationship between environmental contamination, including nitrate, and Iowa’s cancer rates.

The contamination problem is getting worse, not better. An EWG and Iowa Environmental Council analysis of state data from 2002 to 2017 found the average nitrate level in tested private wells nearly doubled over that period. University of Iowa researchers now describe persistently elevated nitrate levels as “the new normal” — a reference to the fact that contamination no longer spikes seasonally but runs at elevated levels year-round.

Bacteria Contamination in Iowa Wells

Bacterial contamination is the other major documented threat to Iowa well owners. Iowa HHS public health tracking data shows that 29% of Iowa private wells tested in 2020 were positive for total coliform bacteria — nearly 1 in 3 in a single year. A longer-term analysis by EWG and the Iowa Environmental Council covering state records from 2002 to 2017 found that more than 40% of wells tested positive for coliform at least once across that 16-year period, with over 4,300 wells showing bacteria every time they were tested — indicating ongoing, structural contamination rather than isolated incidents.

The EPA states there is no safe level of coliform bacteria in drinking water — its presence signals a sanitary defect in the well and indicates the potential presence of more dangerous pathogens including E. coli. Bacteria enter wells through improperly sealed wellheads, flooding, and when septic systems are located too close to well casings. Older bored wells — common in central, south-central and western Iowa — are particularly vulnerable.

Arsenic in Iowa Well Water

Arsenic is a naturally occurring contaminant in Iowa groundwater. The Iowa Cancer Consortium reports that arsenic was found above the federal MCL of 10 micrograms per litre in 14% of tested private wells — a significant proportion. Like nitrate, arsenic is undetectable without laboratory testing: it has no colour, taste or smell. Long-term exposure is linked to cancers of the bladder, kidney, skin, lung and liver, as well as cardiovascular disease and nerve damage.

Iowa’s Grants to Counties programme funds arsenic testing for private well owners through county health departments. The Iowa Department of Health and Human Services recommends that all private well owners test for arsenic — if results show arsenic is not a problem, re-testing is only needed every three years. Reverse osmosis is an effective treatment for arsenic.

PFAS in Iowa Well Water

PFAS contamination in Iowa is primarily linked to military installations that used AFFF firefighting foam. The Iowa Air National Guard bases in Des Moines and Sioux City are documented PFAS sources — the Iowa DNR detected PFAS above safe levels in water in the Sioux City metro area in 2022, with contamination attributed to firefighting foam from the nearby Air National Guard base. At the Des Moines installation, groundwater contamination was identified at levels substantially above the EPA’s health advisory limits.

More than 50 Iowa municipalities joined a class-action lawsuit against 3M and DuPont over PFAS contamination in drinking water sources. While these settlements primarily addressed public water systems, the same contamination plumes affect surrounding groundwater — including private wells. PFAS does not bind easily to soil and can travel significant distances through aquifers over time.

Iowa’s free testing programme does not currently cover PFAS for private wells. If your well is near a military installation, airport, industrial facility or former fire training area, you should arrange PFAS testing through your county health department or a certified private laboratory.

Regulatory Situation for Iowa Well Owners

Private wells in Iowa are not regulated under the federal Safe Drinking Water Act. The Iowa DNR’s Private Well Programme provides regulatory oversight of well construction, renovation and plugging — but has no authority to mandate regular water testing or require remediation if your well is contaminated. Testing and treatment is entirely the responsibility of the well owner.

That said, Iowa has one of the most generous well support programmes in the country. The Grants to Counties programme — funded through the Iowa DNR — provides free water testing for bacteria, nitrate and arsenic through local county health departments, plus financial assistance for well assessment, reconstruction and shock chlorination where contamination is found. Only 5–10% of Iowa well households take advantage of this free programme annually. Contact your county sanitarian to access it.

Check our Iowa municipal water quality page for city-by-city tap water data, including Des Moines, Cedar Rapids and Sioux City, or use our live boil water notice tracker for active advisories across the state.

Known High-Risk Areas in Iowa

If you live near any of the following locations, well water testing is urgent — not precautionary.

How to Test Your Iowa Well Water — and What to Do Next

Iowa well owners are in the unusual position of having one of the nation’s most serious contamination problems alongside one of its most generous free testing programmes. The Grants to Counties programme makes free bacteria, nitrate and arsenic testing available through your county health department — yet research shows fewer than 1 in 10 eligible households use it each year.

Contact your county sanitarian or county health department to arrange free testing. For PFAS testing — not covered by the free programme — the Iowa State Hygienic Laboratory at the University of Iowa (shl.uiowa.edu) offers fee-based testing. If your property is near a military base, airport or known industrial contamination site, PFAS testing should be treated as urgent.

For filter options, our well water filter guide covers reverse osmosis systems for nitrate, arsenic and PFAS, UV disinfection for bacteria, and whole-house well systems for comprehensive treatment. You can also browse our full water filter solutions page or check your ZIP code for local water quality context.

For other Midwest well water risks, see our page on Michigan wells, or browse the private well water directory to find your state. You can also check municipal water quality for Iowa cities — Des Moines and the Iowa state water quality overview — for context on what’s in the wider water supply.