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Well Water Testing · St. Marys, IA

Water testing in St. Marys

Water testing for Iowa homes, above all those on a private well. An accredited laboratory can test the water for coliform bacteria and E. coli…

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St. Marys · Warren County

Well Water Testing in St. Marys

Water testing for Iowa homes, above all those on a private well. An accredited laboratory can test the water for coliform bacteria and E. coli, nitrate, arsenic and more. Iowa DNR recommends testing a private well at least once a year.

St. Marys is a very small Warren County town laid out about 1870 and incorporated in 1923. Housing here runs to a small stock of houses from the years after the roughly 1870 laying out, with early-1900s frame homes, postwar houses and a few newer builds, across the compact townsite of about 0.14 square miles and the farm ground and acreages around it.

St. Marys is served by our Des Moines team →  ·  (563) 517-7815

Well water in Warren County

Iowa DNR says private wells should be tested for coliform bacteria and nitrate every year and for arsenic at least once. Free basic testing is offered through the Grants to Counties Well Testing Program, so ask the Warren County health department. We found no published county-level well-quality numbers for Warren. Statewide, the Iowa Geological Survey says deeper bedrock aquifers carry poorer natural water quality because the water has touched minerals longer, so a well's depth and aquifer matter as much as its location.

County facts checked October 2026 against: iowadnr.gov, iowadnr.gov, igs.iihr.uiowa.edu, naturalresources.extension.iastate.edu.

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Water tests available in St. Marys

Bacteria

Shows whether surface water or waste is reaching the well.

  • Total coliform bacteria
    Surface contamination reaching the well
  • E. coli
    Fecal contamination from septic, manure or wildlife

Health chemicals

No taste, color or smell. These are the long-term health checks.

  • Nitrate
    Fertilizer, septic and manure; highest risk to infants
    10 mg/L (EPA)
  • Arsenic
    Natural arsenic from rock and soil
    10 µg/L (EPA)
  • Lead
    Lead service lines, solder and brass fixtures
  • Manganese
    Natural manganese; a concern for infants
  • Fluoride
    Natural fluoride; dental health
    4.0 mg/L (EPA)
  • Uranium
    Natural radionuclide in groundwater
    30 µg/L (EPA)

Petroleum & solvents

Fuel and chemical spills from old tanks or nearby sites.

  • VOCs (volatile organic compounds)
    Fuels, solvents, degreasers and paints
    Varies by compound (EPA)
  • DRO (diesel range organics)
    Diesel and heating-oil petroleum

Household quality

Staining, scale and taste, and choosing the right treatment.

  • Iron
    Rusty staining and metallic taste
  • Hardness
    Scale buildup; sizing a water softener
    No health standard
  • pH
    Corrosive or scaling water
    6.5 to 8.5, aesthetic (EPA)
  • Sulfate
    Taste and odor; diarrhea risk for infants
    250 mg/L, aesthetic (EPA)

Limits shown are EPA drinking water standards. Your lab report compares each result to the standards that apply.

St. Marys private well testing timeline

Iowa DNR recommends testing a private well at least once a year. Its testing guidance lists coliform bacteria and nitrate every year and arsenic every 3 years, with at least one arsenic test for every well. Source: Iowa DNR
TestYear 1Year 2Year 3Year 4Year 5Year 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.

How far a well must be from common hazards in St. Marys

  • 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
Source: Iowa Administrative Code 567, chapter 49

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 St. Marys: what happens at the sale

  1. 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.
  2. 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.
  3. 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.
  4. 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)).
Source: Iowa Code and Iowa DNR

The paperwork tells you a well exists, not what is in it. Add water testing to your inspection. Get a free instant quote

Questions

Common questions.

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.
Where can a Warren County well owner get free water testing?
The Iowa DNR says free basic testing comes through the Grants to Counties Well Testing Program and tells owners to contact their local county health department. We did not find a Warren County page confirming current details, so call that office before relying on it. DNR's annual guidance covers bacteria and nitrate, with arsenic at least once.
St. Marys covers about 0.14 square miles. Does a lot that small change what gets checked?
Yes, because small lots leave little room for water and for septic fields. Houses sit close together, so where roof runoff and downspouts discharge, whether neighboring grade slopes toward the foundation, and how close sheds, decks and additions sit to the lot line are the things to watch. If a property has its own septic system, Iowa requires an inspection of it before the property transfers under Iowa Code 455B.172, and a small lot makes the field location worth confirming. Warren County is EPA Radon Zone 1, so a 48-hour radon test is a good add-on.
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. A well disclosed on the statement is a reason to have the water tested and the wellhead looked at before closing.
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. A buyer who tests the well before closing knows whether arsenic treatment is a consideration for the property.
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