By the Closer Look Inspectors team · Facts checked October 2026 against Iowa DNR, Iowa HHS, State Hygienic Laboratory and EPA sources · About our inspectors
An arsenic test shows how much of this naturally occurring element is in your well water, reported in micrograms per liter, the same as parts per billion. A 2006 to 2008 University of Iowa survey for Iowa DNR found arsenic in 48 percent of sampled rural wells, and 8 percent were at or above 10 ppb.
All the water tests we offer
Bacteria
Shows whether surface water or waste is reaching the well.
- Surface contamination reaching the well
- Fecal contamination from septic, manure or wildlife
Health chemicals
No taste, color or smell. These are the long-term health checks.
- Fertilizer, septic and manure; highest risk to infants10 mg/L (EPA)
- Natural arsenic from rock and soil10 µg/L (EPA)
- Lead service lines, solder and brass fixtures
- ManganeseNatural manganese; a concern for infants
- FluorideNatural fluoride; dental health4.0 mg/L (EPA)
- UraniumNatural radionuclide in groundwater30 µg/L (EPA)
Petroleum & solvents
Fuel and chemical spills from old tanks or nearby sites.
Household quality
Staining, scale and taste, and choosing the right treatment.
- IronRusty staining and metallic taste
- HardnessScale buildup; sizing a water softenerNo health standard
- pHCorrosive or scaling water6.5 to 8.5, aesthetic (EPA)
- SulfateTaste and odor; diarrhea risk for infants250 mg/L, aesthetic (EPA)
Limits shown are EPA drinking water standards. Compare your lab results with these values.
Health standard: EPA and Iowa standard for public water: 0.010 mg/L (10 ppb), which Iowa DNR says private well owners should use as their benchmark.
Where arsenic comes from in Iowa
Arsenic is a natural element found in some Iowa soils and bedrock. Iowa DNR says it occurs in sulfide minerals that were deposited in the soil and bedrock over millions of years. It can enter groundwater from the rock and soil around a well. The State Hygienic Laboratory says arsenic is prevalent in north-central Iowa but can be found anywhere in the state. In the University of Iowa survey, high results were most common in the north-central region. Thirty counties had wells at or above 10 ppb. The Des Moines Lobe, a glacial area in north-central Iowa, is known to have natural arsenic deposits. The survey found no link between arsenic and well depth: 24 of 267 wells deeper than 100 feet were at or above 10 ppb. Well age and the season of sampling also showed no link. DNR says many areas of the state have not been tested for arsenic.
Health effects and who is most at risk
Long-term exposure to arsenic above 10 ppb raises the risk of chronic health issues like cancer. The State Hygienic Laboratory links lifetime drinking of arsenic-containing water to an increased risk of cancer of the skin, bladder, lung, kidney, nasal passages, liver or prostate. It is also linked to diabetes and to cardiovascular, immune and nerve disorders. Long-term exposure can darken the skin and cause small corns or warts. EPA says fetuses, infants and children are especially vulnerable because of their smaller bodies and rapid growth. The 10 ppb limit is based on an average person drinking 2 liters of water a day for a lifetime. EPA recommends against using water above the limit as a long-term source for drinking or cooking. Bathing is not a significant risk because arsenic is not readily absorbed through the skin. Although the amount swallowed is minimal, using clean water for brushing teeth is advisable.
Signs and when to test
You cannot see, taste or smell arsenic, and only a lab test shows it. DNR recommends at least one arsenic test on every private well. DNR's schedule lists arsenic every 3 years, and the State Hygienic Laboratory's arsenic fact sheet says every 5 years. Test sooner after the well is rehabilitated or when new irrigation or construction starts near it. DNR says you may need to test more often if a result is elevated or if other wells nearby show a change in arsenic. Arsenic comes from the rock and is not expected to change much with the seasons, so any time of year works. A home purchase is a sensible time for a baseline result. The State Hygienic Laboratory's homebuyer guide says to test well water early so there are no delays in the home closing.
If your result is high: treatment options
DNR says repeat testing lets you decide when to install a treatment system or when to stop drinking the water. Use bottled water or another known safe source in the meantime. Boiling does not remove arsenic. It only concentrates it. Reverse osmosis, distillation, activated alumina and anionic resin can remove arsenic. Iowa HHS calls reverse osmosis the most reliable method. A point-of-use unit at the kitchen sink or refrigerator tap can treat drinking water. Whole-house systems also exist. The form of arsenic in the water, known as its speciation, affects how easily it can be removed. Chlorine does not remove arsenic. DNR also lists repairing the well or water system, connecting to a known safe water supply, or replacing the existing supply as options. It says to talk with a DNR-certified well contractor. Choose certified equipment and work with a trained technician. Retest after a unit is installed to confirm it works.
Facts checked October 2026 against: iowadnr.gov, iowadnr.gov, hhs.iowa.gov, iowadnr.gov, services.shl.uiowa.edu, epa.gov, shl.uiowa.edu, iowadnr.gov, iowadnr.gov, iowadnr.gov, shl.uiowa.edu, epa.gov.
Iowa private well testing timeline
| Test | Year 1 | Year 2 | Year 3 | Year 4 | Year 5 | Year 6 |
|---|---|---|---|---|---|---|
| Coliform bacteria | ||||||
| Nitrate | ||||||
| Arsenic |
When to test your water
- Every yearColiform bacteria and nitrate, the basic safety checks for a private well.
- At least onceArsenic and manganese. Iowa DNR's testing list repeats arsenic every 3 years.
- Before a baby drinks the waterNitrate. Water above 10 mg/L as nitrogen should not be used for infant formula or juice.
- When you buy a homeA full baseline while you can still ask questions or negotiate.
- New well or well workWhen a well is new and after service on the well or pump.
- After a flood or power outageIf flood water was near or reached the well, or an outage dropped the water pressure.
- When taste, color or smell changesA change in the water is a reason to test.
- Near a fuel tankVOCs, plus DRO for diesel and fuel oil. Iowa DNR names gasoline among the VOCs some wells are susceptible to, and Iowa's well rules list 100 feet between a well and a liquid fuel storage tank other than propane.
- City water in an older homeLead. Iowa DNR says homes built before 1986 are more likely to have lead pipes, fixtures and solder.
Based on: Iowa DNR private wells, Iowa DNR testing frequency, Iowa DNR why test, Iowa DNR floods, State Hygienic Laboratory, 567 IAC 49.
How to get it done
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- Get certified lab resultsA certified laboratory analyzes the water and reports each result.
How far a well must be from common hazards in Iowa
- Property line4 ft
- Building sewer line10 ft
- LP gas tank15 ft
- Roadside ditch15 ft
- Stream, pond, lake or wetland25 ft
- Septic tank50 ft
- Septic absorption field100 ft
- Fuel oil or gasoline tank100 ft
- Fertilizer or chemical storage150 ft
Septic, feedlot or fuel tank near the well? A coliform and nitrate test shows whether it is reaching the water. Get a free instant quote
Buying a home with a well in Iowa: what happens at the sale
- Groundwater Hazard StatementIowa Code 558.69 requires a groundwater hazard statement filed with the declaration of value when a listed condition (including any known well and its status under 455B.190, or a private sewage disposal system) exists on the property, signed by a seller or agent, with a copy given to the buyer.
- Wells on the propertyIf known wells are on the property, the statement must give the approximate location of each and its status under Iowa Code 455B.190 (abandoned wells properly plugged); the owner is responsible for the accuracy of the information.
- Septic time-of-transfer inspectionIowa Code 455B.172(11) requires a private sewage disposal system serving a building to be inspected before any transfer of ownership, by a DNR-certified inspector, and the county recorder will not record the deed without the report or a binding acknowledgment.
- Failing systemsA system that is failing to treat wastewater must be renovated to current standards by the seller or, by agreement and within a reasonable time set by the county board of health or DNR, by the buyer (455B.172(11)(c)).
The paperwork tells you a well exists, not what is in it. Add water testing to your inspection. Get a free instant quote
Quick answers
How common is arsenic in Iowa well water?
In a 2006 to 2008 University of Iowa survey for Iowa DNR, arsenic was detected in 48 percent of sampled rural wells. Eight percent were at or above 10 ppb. High results were most common in north-central Iowa, and 30 counties had at least one well at or above 10 ppb. DNR says many areas have not been tested for arsenic, and only a lab test shows a well's level.
What is the safe level of arsenic in drinking water in Iowa?
The EPA and Iowa standard is 0.010 mg/L, which is 10 parts per billion. It assumes an average person drinking 2 liters of water a day for a lifetime. EPA's health goal for arsenic is 0. Private wells are not regulated for arsenic, so DNR tells owners to use the EPA standard as the benchmark for a well.
How often should I test my Iowa well for arsenic?
Iowa DNR recommends at least one arsenic test on every private well. DNR's schedule lists arsenic every 3 years, and the State Hygienic Laboratory's arsenic fact sheet says every 5 years. The fact sheet also says to test again when a well is rehabilitated or irrigation or construction starts nearby. DNR says an elevated result may mean more frequent testing. Arsenic is not expected to change much with the seasons.
How do you remove arsenic from well water?
Reverse osmosis, distillation, activated alumina and anionic resin can remove arsenic, and Iowa HHS calls reverse osmosis the most reliable. Boiling does not work. It only concentrates arsenic. The form of arsenic in the water affects how easily it can be removed. Drinking water should be retested for arsenic after a unit is installed. DNR also lists repairing the well or water system, connecting to a known safe water supply, or replacing the supply as options.
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