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Well Water Testing · St. Charles, MN

Water testing in St. Charles

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

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St. Charles · Winona County

Well Water Testing in St. Charles

Water testing for Minnesota homes, above all those on a private well. An accredited laboratory tests the water for coliform bacteria and E. coli, nitrate, arsenic, lead, manganese, VOCs (volatile organic compounds), DRO (diesel range organics), iron, hardness, pH, fluoride, sulfate and uranium. The Minnesota Department of Health recommends testing a private well for coliform bacteria every year, nitrate every other year, and arsenic and lead at least once.

St. Charles is a small southeastern town on the bluff-country edge. Housing here runs to small bluff-country town homes, across the town core.

Questions about a St. Charles home?  ·  Call or text (612) 457-1634

Well water in Winona County

MDA tested 13 Winona County townships in 2016-2017. The initial dataset of 940 wells had 19.1% at or above 10 mg/L nitrate-nitrogen. After removing 209 wells with other likely nitrate sources or well problems, the final dataset of 731 wells was 7.1%, and four townships were over 10%. Fremont was highest at 42.9%, followed by Utica at 19.6%. MDH describes karst as the most common geology in southeast Minnesota, where surface water can reach groundwater in hours or days.

County facts checked October 2026 against: mda.state.mn.us, mda.state.mn.us, Minnesota Department of Health.

Well water around St. Charles, Winona County

St. Charles, MN water testing: older Saint Paul style two-story home with mature trees in winter snow
E. coli: a sign of fecal contamination →
Rochester area newer home on a rural lot in summer (Winona County, Minnesota)
VOCs: fuels, solvents and degreasers →
St. Charles, MN water testing: well cap in the foreground, ranch home on acreage behind it in southeastern Minnesota bluff country in winter snow
Nitrate: EPA limit 10 mg/L, highest risk to infants →

See all St. Charles inspections →  ·  More about well water testing →  ·  Every water test, explained →

Water tests available in St. Charles

Bacteria

Shows whether surface water or waste is reaching the well.

  • Total coliform bacteria
    Surface contamination reaching the well
    None should be present (MDH)
  • E. coli
    Fecal contamination from septic, manure or wildlife
    None should be present (MDH)

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 Minnesota rock and soil
    10 µg/L (EPA)
  • Lead
    Lead service lines, solder and brass fixtures
    No safe level (MDH)
  • Manganese
    Natural manganese; a concern for infants
    100 µg/L for infants (MDH guidance)
  • 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
    No limit of its own; a petroleum screen (MPCA)

Household quality

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

  • Iron
    Rusty staining and metallic taste
    0.3 mg/L, aesthetic (MDH)
  • 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 from MDH, EPA and MPCA. Your lab report compares each result to these values.

St. Charles private well testing timeline

Minnesota Department of Health schedule: coliform bacteria every year, nitrate every other year, arsenic and lead at least once. Source: MDH
TestYear 1Year 2Year 3Year 4Year 5Year 6
Coliform bacteria
Nitrate
Arsenic
Lead

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.

Nitrate in Winona County wells

7.1%

7.1% of 731 wells tested in 13 townships (final dataset) were at or over the 10 mg/L nitrate standard (MDA township testing, 2016-2017).

Source: Minnesota Department of Agriculture township testing

Township numbers are averages. Only a test of your own well tells you its nitrate level. Get a free instant quote

Buying a home with a well in St. Charles: the disclosure rules

  1. Before the purchase agreementThe seller discloses in writing every known well and whether it is in use, not in use or sealed.
  2. At closingA well disclosure certificate is signed, unless the deed says the seller knows of no wells.
  3. If a well was hiddenA seller who knew of an undisclosed well can owe the sealing cost and attorney fees if the buyer sues within six years.
Source: Minnesota Statutes 103I.235

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

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

  • Building (closest projection)3 ft
  • Lake, river, stream or pond35 ft
  • Septic tank50 ft
  • Drainfield (soil dispersal area)50 ft (100 ft sensitive well)
  • Animal feedlot or building (over 1 animal unit)50 ft
  • Cesspool or seepage pit75 ft (150 ft sensitive well)
  • Unroofed feedlot, 300+ animal units100 ft
  • Unprotected petroleum tank, 1,100+ gallons150 ft
Source: Minnesota Rules 4725.4450 and 4725.4350

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

Questions

Common questions.

Who needs well water testing?
Any home on a private well, and above all when you are buying one. A private well is not regulated like a city water system, so the owner is responsible for knowing what is in the water. Testing before closing tells you whether the water needs treatment while you can still ask questions or negotiate.
What does the water panel cover?
The panel covers coliform bacteria and E. coli, nitrate, arsenic, lead, manganese, VOCs (volatile organic compounds), DRO (diesel range organics), iron, hardness, pH, fluoride, sulfate and uranium. Bacteria and nitrate are the short-term health checks. Arsenic, lead, manganese and uranium are the ones you cannot see or taste. VOCs and DRO screen for solvents and petroleum, such as fuel from an old oil tank or a nearby leak site. Iron, hardness, pH and sulfate explain staining, scale, odor and wear on plumbing and appliances.
How often should a well be tested?
The Minnesota Department of Health recommends coliform bacteria every year, nitrate every other year, and arsenic and lead at least once. Test again after flooding, after any work on the well, or if the taste, color or smell of the water changes.
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.
Which Winona County townships had the highest well nitrate?
In MDA's 2016-2017 final dataset of 731 wells, Fremont Township had 42.9% of wells at or above 10 mg/L, then Utica at 19.6% and St. Charles at 14.5%. The county total was 7.1%. Those are township samples, not a prediction for your property.
My home is on city water. Is water testing still worth it?
Often yes. Community water systems follow EPA testing rules and report results in an annual Consumer Confidence Report, but that report does not measure your own plumbing. MDH and EPA say lead enters mainly from service lines and plumbing materials, and the only way to know is a tap test. MDH recommends an accredited lab, and your utility can say whether your home has a lead service line.
When should a home be tested for DRO or VOCs?
MDH suggests considering a VOC test when a well is near fuel tanks or a commercial or industrial area. MPCA reports petroleum has leaked at about 22,000 Minnesota sites, including home heating-oil tanks, and releases can threaten drinking water and send vapors into buildings. Reasons to test include a nearby leak site, a former or buried fuel tank, or a fuel odor or sheen. MPCA's leaking-tank-site database shows reported releases.
Do you cover St. Charles?
Yes — southeastern bluff country is in range. Runoff patterns on bluff-edge ground make grading and foundation moisture the leading items, followed by the usual systems read by age.
How does lead get into well water?
Lead is not usually in the well water itself. It enters through plumbing, most often lead pipes. Brass faucets and valves can release lead in their first months, some submersible pumps made before 1995 may contain leaded brass, and lead packers were used in wells drilled before 1980. Lead dissolves more the longer water sits in plumbing.
Can I boil well water that tested positive for coliform?
MDH says boiled or bottled water can be used for drinking and cooking until the problem is fixed. However, do not boil the water if nitrate or arsenic was also detected, because boiling can increase their concentration. In that case use bottled water or another safe source until the well is treated and retested.
What is a well pit and why is it a concern?
Older wells were often finished in pits below ground so pipes would not freeze. The Department of Health says pits are a health hazard because flood water and runoff can flow into the well, and a safety hazard because people, animals, or equipment can fall in and toxic gases can build up. Current rules prohibit them; MDH recommends upgrading with a pitless adapter. A coliform test shows whether bacteria are getting in.
How common is arsenic in Minnesota well water?
The Department of Health says about 40 percent of Minnesota wells have arsenic in the water. It occurs naturally in rocks and soil, levels can differ between wells even within a small area, and you cannot taste, see, or smell it. The EPA limit for community water systems is 10 micrograms per liter. Only a lab test shows the arsenic level in a specific well.
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