By the Closer Look Inspectors team · Facts checked October 2026 against Iowa DNR, Iowa Code and State Hygienic Laboratory sources · About our inspectors
Water testing for Iowa homes, on a private well or city water. An accredited laboratory can test for coliform bacteria, E. coli, nitrate, arsenic, lead, VOCs, DRO and more. Add it to your home inspection in the free instant quote below.
On this page
Every test at a glanceHow often to testIowa wells, by the numbersIowa well rulesWater testing by countyQuick answersEvery water test at a glance
Bacteria
Shows whether surface water or waste is reaching the well.
- Total coliform bacteriaSurface contamination reaching the well
- E. coliFecal contamination from septic, manure or wildlife
Health chemicals
No taste, color or smell. These are the long-term health checks.
- NitrateFertilizer, septic and manure; highest risk to infants10 mg/L (EPA)
- ArsenicNatural arsenic from rock and soil10 µg/L (EPA)
- LeadLead 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.
- VOCs (volatile organic compounds)Fuels, solvents, degreasers and paintsVaries by compound (EPA)
- DRO (diesel range organics)Diesel and heating-oil petroleum
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. Your lab report compares each result to the standards that apply.
Water testing in Iowa, in pictures
How often to test a private well in Iowa
Iowa private well testing timeline
| Test | Year 1 | Year 2 | Year 3 | Year 4 | Year 5 | Year 6 |
|---|---|---|---|---|---|---|
| Coliform bacteria | ||||||
| Nitrate | ||||||
| Arsenic |
Test again any time after flooding, after work on the well, or when the water's taste, color or smell changes, and always when you buy a home with a well.
Iowa wells, by the numbers
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
Iowa well rules every buyer should know
Does Iowa offer free or low-cost private well testing?
Yes. Iowa's Private Well Grants program, also called Grants to Counties, is run through Iowa HHS with DNR technical help. It provides free water testing for private well owners. The listed analytes are bacteria/E. coli/coliform and nitrate annually, plus arsenic and manganese every 3 years. A county health specialist collects the sample, so you start by contacting your county health department and asking to take part in the program.
Why it matters: Testing is the only way to know whether a well's water is safe, and a baseline result helps a buyer judge the water at a home with a private well.
Source: iowadnr.gov, hhs.iowa.gov
Who do I call to get my well tested?
Call your county environmental health department and ask for the county sanitarian (environmental health specialist). DNR says local county health departments can help but you must contact them to start testing. Under the grant guidance the county health specialist must collect the samples, and the sanitarian can also help interpret results. DNR keeps a county contact spreadsheet that ISU Extension links to from its drinking water page.
Why it matters: A lab result from a properly collected sample is what turns a guess about well water into a documented answer.
Source: iowadnr.gov, hhs.iowa.gov, naturalresources.extension.iastate.edu
Can I order a test kit from the State Hygienic Laboratory instead?
Yes. If the sanitarian cannot collect your sample or you prefer to do it yourself, the State Hygienic Laboratory at the University of Iowa supplies sampling kits with sterile bottles and instructions. Use only the bottle the lab provides, since the coliform and nitrate bottles are specially prepared. The lab says samples should reach it within 48 hours of collection, so ship the same day and avoid Fridays and holidays.
Why it matters: A water test during the sale of a home gives both sides lab data on the well rather than assumptions.
Source: shl.uiowa.edu, naturalresources.extension.iastate.edu
How often should a private well be tested in Iowa?
Iowa DNR recommends every private well used for drinking be tested at least once a year. Coliform bacteria and nitrate are annual tests. Also test when a well is new, after the well, pump or water system is serviced, after a power outage that drops water pressure, and when the water changes in appearance, smell or taste. Arsenic is listed every 3 years on the DNR page, and at least once for every well.
Why it matters: Annual coliform and nitrate results show whether a well has changed since the last sample, which is the point of testing when buying a home.
Source: iowadnr.gov, shl.uiowa.edu
Is nitrate in well water dangerous for infants?
Yes. The State Hygienic Laboratory says nitrate above 10 mg/L as N may pose a serious health hazard for infants, and such water should not be used in infant formula or juice. Infants fed it can develop methemoglobinemia, or blue baby syndrome, a life-threatening illness. Boiling does not remove nitrate. Shallow wells and poorly located, built or maintained wells are more likely to have nitrate, so annual testing is the way to know.
Why it matters: A nitrate test is the only way to learn whether the water at a home with young children is below the 10 mg/L limit.
Source: shl.uiowa.edu, hhs.iowa.gov
Is there arsenic in Iowa well water?
Arsenic occurs naturally in Iowa rocks and soil, and DNR says it is present at some level in groundwater in many areas of the state. A 2006-2008 University of Iowa survey for DNR found detectable arsenic in 48 percent of 475 sampled rural wells, and 8 percent were at or above 0.01 mg/L (10 ppb). High arsenic was most common in north-central Iowa. Only a lab test shows your well's level.
Why it matters: Arsenic cannot be seen, tasted or smelled, so a lab test during a home purchase is how a buyer learns the level in that well.
Source: iowadnr.gov, iowadnr.gov, shl.uiowa.edu
What is the arsenic limit, and can I boil it out?
The Iowa and U.S. EPA health standard for arsenic in drinking water is 0.010 mg/L, or 10 parts per billion. Boiling does not remove arsenic. The State Hygienic Laboratory lists distillation, reverse osmosis, activated alumina and anionic resin as treatments, and suggests testing arsenic speciation to choose the most effective option. If a test is elevated, DNR says you may need to test more often.
Why it matters: A buyer who tests the well before closing knows whether arsenic treatment is a consideration for the property.
Source: iowadnr.gov, shl.uiowa.edu, iowadnr.gov
What does a positive coliform or E. coli result mean?
Per the State Hygienic Laboratory, absent coliform and E. coli means the water is bacterially safe. Present total coliform means unsafe with potential health concerns. Present coliform and E. coli means unsafe with serious health concerns, because a pathway from a waste source such as a septic tank or feedlot may exist. Short term, boil water for one minute or use a known safe source, then find and fix how bacteria are entering the system.
Why it matters: A coliform result is a lab indicator of a possible sanitary defect, and a home inspection of the wellhead looks for visible defects like a loose cap or poor drainage.
Source: shl.uiowa.edu, iowadnr.gov
Should I test my well after a flood?
Yes. Iowa DNR says never consume water from a well if flood water may have reached it, and test to find out if it is safe. Test for coliform and E. coli, and nitrate. Floods can raise groundwater loading near a well and surface water can enter through casing defects. Standard bacteria tests do not detect Giardia or Cryptosporidium, so ask the county about State Hygienic Laboratory parasite testing if you suspect flood contamination.
Why it matters: After a flood, only lab testing shows whether a well is safe, and a wellhead check can note casing or cap damage.
Source: iowadnr.gov, shl.uiowa.edu
How is a well shock chlorinated, and what does Iowa DNR say about retesting?
DNR's flood guidance says if a well is positive for coliform or E. coli, purge and shock chlorinate the well and water system, then retest for bacteria, fecal coliform and nitrate 7 to 10 days later, repeating until there is zero coliform and fecal coliform. Iowa's well rules (567 IAC 49.24) call for chlorine to reach every part of the well and stay in contact long enough. Shock chlorination does not remove Giardia or Cryptosporidium.
Why it matters: A follow-up lab test is the check that a disinfection actually cleared bacteria from the well.
Source: iowadnr.gov, legis.iowa.gov, hhs.iowa.gov
What is the Iowa Groundwater Hazard Statement?
Under Iowa Code 558.69, a groundwater hazard statement must be submitted with the declaration of value when property is conveyed, if any listed condition exists. It covers known private burial sites, wells and their status under section 455B.190, hazardous solid waste disposal sites, underground storage tanks, hazardous waste, and private sewage disposal systems. A seller or agent signs it, and the buyer must be given a copy.
Why it matters: A well disclosed on the statement is a reason to have the water tested and the wellhead looked at before closing.
Source: legis.iowa.gov
Does a septic system have to be inspected when an Iowa home is sold?
Yes, in most sales. Iowa Code 455B.172(11) requires a private sewage disposal system serving a building to be inspected before any transfer of ownership, and the county recorder will not record the deed without the inspector's report or a binding acknowledgment to inspect when weather prevents it. Only a DNR-certified time-of-transfer inspector may do it. Exemptions in the statute include transfers where the system was installed not more than two years earlier. An inspection is valid for two years.
Why it matters: Because septic and well separation distances matter for water quality, a buyer of a home with both gets a fuller picture by testing the water alongside the septic report.
Source: legis.iowa.gov, legis.iowa.gov
Is there money to help plug an old well or cistern?
Yes. DNR's Private Well Grants page lists funding for well plugging and cistern plugging, along with shock chlorination, well assessments and well reconstruction or renovation. To use it, contact your county health department first, hire a DNR-certified well contractor, tell them you are using grant funds, and submit the completed DNR form and an itemized paid invoice. The county reimburses you directly after review and approval.
Why it matters: If a property has an old well or cistern, the grant program is a way a new owner can address it, and the water test shows whether it has affected the supply.
Source: iowadnr.gov, hhs.iowa.gov
Do I need a permit to drill or replace a private well?
Yes. Under 567 IAC 49.3(3) and Iowa Code 455B.187(2), a landowner cannot construct a new private well without first getting a well construction permit from DNR or a county with delegated authority. A permit is also required for replacement wells and for changes to a well's physical dimensions. The permit requires construction by a certified well contractor, and it is not transferable and expires one calendar year after issuance.
Why it matters: A new or replaced well should be tested, and Iowa's rules call for a water sample 10 to 30 days after a new or reconstructed well goes into service.
Source: legis.iowa.gov
Who is allowed to do well work in Iowa?
Iowa requires well services to be done by a DNR-certified well contractor who is on site and in direct charge of the work, under 567 IAC 82.2(1) and 49.4(3). The one exception is that a person may perform well services on their own property. DNR certifies well drillers, pump installers and well plugging contractors, and they have different scopes. You can check a contractor's status on DNR's lists.
Why it matters: A home inspector or tester does not do licensed well work; testing and a visual check of the wellhead help decide whether to call a certified contractor.
Source: legis.iowa.gov, iowadnr.gov
What does Iowa say about the wellhead itself?
Under 567 IAC 49.17, a well not in a wellhouse needs a cap that seals tightly against the casing, and the casing must terminate at least one foot above finished grade. A cap on a well with a pitless adapter needs a screened vent at least 12 inches above the ground. Section 49.8 says wells cannot be located in basements or in frost pits. These are the construction rules for new wells.
Why it matters: Cap, casing height and drainage around the wellhead are visible items covered in a home inspection, and a bacteria test shows whether they are doing their job.
Source: legis.iowa.gov
When should I test the water if I'm buying a home with a well?
DNR recommends testing when a well is brand new, after any service on the well or pump, after power outages that cause loss of pressure, and when water looks, smells or tastes different. Treat a purchase like a new-owner situation: the owner of the well is responsible for its testing. Coliform bacteria and nitrate are annual tests, and arsenic is recommended at least once.
Why it matters: A coliform, nitrate and arsenic test on the well before closing gives the buyer a lab result for the water they will be drinking.
Source: iowadnr.gov, shl.uiowa.edu, hhs.iowa.gov
Water testing by county
Appanoose County
Boone County
Butler County
Cerro Gordo County
Clarke County
Dallas County
Decatur County
Floyd County
Franklin County
Hamilton County
Hancock County
Hardin County
Humboldt County
Jasper County
Kossuth County
Lucas County
Madison County
Mahaska County
Marion County
Mitchell County
Monroe County
Polk County
Ringgold County
Story County
Union County
Warren County
Wayne County
Webster County
Winnebago County
Worth County
Wright County
Quick answers
Who needs well water testing in Iowa?
Any home on a private well, and above all one you are buying. Iowa DNR recommends testing a private well at least once a year, and also when a well is new, after work on the well or pump, and when the water changes in look, smell or taste.
Is well water testing part of the home inspection?
It is an add-on. Add it to your home inspection quote. Testing early in your inspection window leaves time to act on the results.
Does Iowa offer free or low-cost private well testing?
Yes. Iowa's Private Well Grants program, also called Grants to Counties, is run through Iowa HHS with DNR technical help. It provides free water testing for private well owners. The listed analytes are bacteria/E. coli/coliform and nitrate annually, plus arsenic and manganese every 3 years. A county health specialist collects the sample, so you start by contacting your county health department and asking to take part in the program.
Who do I call to get my well tested?
Call your county environmental health department and ask for the county sanitarian (environmental health specialist). DNR says local county health departments can help but you must contact them to start testing. Under the grant guidance the county health specialist must collect the samples, and the sanitarian can also help interpret results. DNR keeps a county contact spreadsheet that ISU Extension links to from its drinking water page.
Can I order a test kit from the State Hygienic Laboratory instead?
Yes. If the sanitarian cannot collect your sample or you prefer to do it yourself, the State Hygienic Laboratory at the University of Iowa supplies sampling kits with sterile bottles and instructions. Use only the bottle the lab provides, since the coliform and nitrate bottles are specially prepared. The lab says samples should reach it within 48 hours of collection, so ship the same day and avoid Fridays and holidays.
How often should a private well be tested in Iowa?
Iowa DNR recommends every private well used for drinking be tested at least once a year. Coliform bacteria and nitrate are annual tests. Also test when a well is new, after the well, pump or water system is serviced, after a power outage that drops water pressure, and when the water changes in appearance, smell or taste. Arsenic is listed every 3 years on the DNR page, and at least once for every well.
Is nitrate in well water dangerous for infants?
Yes. The State Hygienic Laboratory says nitrate above 10 mg/L as N may pose a serious health hazard for infants, and such water should not be used in infant formula or juice. Infants fed it can develop methemoglobinemia, or blue baby syndrome, a life-threatening illness. Boiling does not remove nitrate. Shallow wells and poorly located, built or maintained wells are more likely to have nitrate, so annual testing is the way to know.
Is there arsenic in Iowa well water?
Arsenic occurs naturally in Iowa rocks and soil, and DNR says it is present at some level in groundwater in many areas of the state. A 2006-2008 University of Iowa survey for DNR found detectable arsenic in 48 percent of 475 sampled rural wells, and 8 percent were at or above 0.01 mg/L (10 ppb). High arsenic was most common in north-central Iowa. Only a lab test shows your well's level.
What is the arsenic limit, and can I boil it out?
The Iowa and U.S. EPA health standard for arsenic in drinking water is 0.010 mg/L, or 10 parts per billion. Boiling does not remove arsenic. The State Hygienic Laboratory lists distillation, reverse osmosis, activated alumina and anionic resin as treatments, and suggests testing arsenic speciation to choose the most effective option. If a test is elevated, DNR says you may need to test more often.
What does a positive coliform or E. coli result mean?
Per the State Hygienic Laboratory, absent coliform and E. coli means the water is bacterially safe. Present total coliform means unsafe with potential health concerns. Present coliform and E. coli means unsafe with serious health concerns, because a pathway from a waste source such as a septic tank or feedlot may exist. Short term, boil water for one minute or use a known safe source, then find and fix how bacteria are entering the system.
Should I test my well after a flood?
Yes. Iowa DNR says never consume water from a well if flood water may have reached it, and test to find out if it is safe. Test for coliform and E. coli, and nitrate. Floods can raise groundwater loading near a well and surface water can enter through casing defects. Standard bacteria tests do not detect Giardia or Cryptosporidium, so ask the county about State Hygienic Laboratory parasite testing if you suspect flood contamination.
How is a well shock chlorinated, and what does Iowa DNR say about retesting?
DNR's flood guidance says if a well is positive for coliform or E. coli, purge and shock chlorinate the well and water system, then retest for bacteria, fecal coliform and nitrate 7 to 10 days later, repeating until there is zero coliform and fecal coliform. Iowa's well rules (567 IAC 49.24) call for chlorine to reach every part of the well and stay in contact long enough. Shock chlorination does not remove Giardia or Cryptosporidium.
What is the Iowa Groundwater Hazard Statement?
Under Iowa Code 558.69, a groundwater hazard statement must be submitted with the declaration of value when property is conveyed, if any listed condition exists. It covers known private burial sites, wells and their status under section 455B.190, hazardous solid waste disposal sites, underground storage tanks, hazardous waste, and private sewage disposal systems. A seller or agent signs it, and the buyer must be given a copy.
Does a septic system have to be inspected when an Iowa home is sold?
Yes, in most sales. Iowa Code 455B.172(11) requires a private sewage disposal system serving a building to be inspected before any transfer of ownership, and the county recorder will not record the deed without the inspector's report or a binding acknowledgment to inspect when weather prevents it. Only a DNR-certified time-of-transfer inspector may do it. Exemptions in the statute include transfers where the system was installed not more than two years earlier. An inspection is valid for two years.
Is there money to help plug an old well or cistern?
Yes. DNR's Private Well Grants page lists funding for well plugging and cistern plugging, along with shock chlorination, well assessments and well reconstruction or renovation. To use it, contact your county health department first, hire a DNR-certified well contractor, tell them you are using grant funds, and submit the completed DNR form and an itemized paid invoice. The county reimburses you directly after review and approval.
Do I need a permit to drill or replace a private well?
Yes. Under 567 IAC 49.3(3) and Iowa Code 455B.187(2), a landowner cannot construct a new private well without first getting a well construction permit from DNR or a county with delegated authority. A permit is also required for replacement wells and for changes to a well's physical dimensions. The permit requires construction by a certified well contractor, and it is not transferable and expires one calendar year after issuance.
Who is allowed to do well work in Iowa?
Iowa requires well services to be done by a DNR-certified well contractor who is on site and in direct charge of the work, under 567 IAC 82.2(1) and 49.4(3). The one exception is that a person may perform well services on their own property. DNR certifies well drillers, pump installers and well plugging contractors, and they have different scopes. You can check a contractor's status on DNR's lists.
What does Iowa say about the wellhead itself?
Under 567 IAC 49.17, a well not in a wellhouse needs a cap that seals tightly against the casing, and the casing must terminate at least one foot above finished grade. A cap on a well with a pitless adapter needs a screened vent at least 12 inches above the ground. Section 49.8 says wells cannot be located in basements or in frost pits. These are the construction rules for new wells.
When should I test the water if I'm buying a home with a well?
DNR recommends testing when a well is brand new, after any service on the well or pump, after power outages that cause loss of pressure, and when water looks, smells or tastes different. Treat a purchase like a new-owner situation: the owner of the well is responsible for its testing. Coliform bacteria and nitrate are annual tests, and arsenic is recommended at least once.
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