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Well Water Testing · St. Peter, MN

Water testing in St. Peter

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. Peter · Nicollet County

Well Water Testing in St. Peter

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 year, and arsenic and lead at least once.

St. Peter is a Minnesota River valley town of historic homes and university-area housing. Housing here runs to historic 1800s and early-1900s homes along Minnesota Avenue and near Gustavus Adolphus College, postwar neighborhoods, and the many roofs and homes rebuilt after the 1998 tornado, across the historic core along Minnesota Avenue, the college hill, and the postwar and post-1998 neighborhoods on the edges.

St. Peter is served by our Mankato team →  ·  (507) 721-3820

Well water in Nicollet County

MDA's 2018 township testing in Nicollet County's Ridgely Township found wells at or over the 10 mg/L nitrate limit. It was a small sample from one township, but it shows nitrate can matter here. MDH says arsenic occurs statewide and about 40 percent of new wells since 2008 had a detection. MDH also gives 100 µg/L as the manganese level for infant formula and says southwestern Minnesota tends high.coli, nitrate, arsenic, lead, manganese, iron, hardness, pH, fluoride, sulfate, uranium, VOCs and DRO (diesel range organics) through an accredited lab.

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

Well water around St. Peter, Nicollet County

St. Peter, MN water testing: whole-house sediment filter canister in a Minnesota utility closet
Nitrate: EPA limit 10 mg/L, highest risk to infants →
Water heater beside a well pressure tank in a 1970s unfinished Minnesota basement (Nicollet County, Minnesota)
Arsenic: about 10% of Minnesota wells exceed the standard →
St. Peter, MN water testing: copper main water line with shutoff valve in an older fieldstone Minnesota basement
Lead: MDH says no level is safe →

Home inspection in St. Peter →  ·  More about well water testing →  ·  Every water test, explained →

Pairs well with:

Septic inspection in St. PeterRadon testing in St. PeterSewer scope in St. Peter

Water tests available in St. Peter

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. Compare your lab results with these values.

St. Peter private well testing timeline

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

When to test your water

  • Every yearColiform bacteria and nitrate, the basic safety checks for a private well. Nitrate can come from fertilizer, septic systems and animal waste.
  • At least onceArsenic and lead. Arsenic can differ even between neighboring wells.
  • Before a baby drinks the waterColiform bacteria, nitrate, arsenic, lead and manganese. MDH recommends testing a private well for all five before a baby drinks the water.
  • When you buy a homeA full baseline while you can still ask questions or negotiate.
  • After flooding or well workFlooding and repairs to the well are reasons to test again.
  • When taste, color or smell changesMDH says a change in taste, smell or look is a reason to test for coliform bacteria.
  • Near a fuel tank or industrial siteVOCs, plus DRO for diesel and heating oil. MDH says to consider a VOC test if the well is near fuel tanks or a commercial or industrial area.
  • City water in an older homeLead. MDH says homes built before 1940 may have lead service lines, and plumbing parts made before 1986 may contain lead.

Based on: MDH well testing, MDH coliform bacteria, MDH nitrate, MDH water for babies, MDH flood precautions, MDH lead.

How to get it done

  1. Choose your testsPick the water testing you need in the free instant quote.
  2. Pick a timeBook online. The quote takes about 30 seconds.
  3. Get certified lab resultsA certified laboratory analyzes the water and reports each result.

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Buying a home with a well in St. Peter: 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. Peter

  • 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 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.
What did nitrate testing show in Nicollet County?
MDA sampled wells in Ridgely Township in 2018 and found some at or over the 10 mg/L nitrate limit. That is a small number of wells in one township, so it does not describe the whole county or your well. MDH lists nitrate testing every year for private wells, and it matters most with an infant in the home.
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 inspect St. Peter homes?
Yes, from our Mankato base. St. Peter's historic core gets the full older-home treatment — stone foundations, original wiring, chimneys, clay laterals — and a lot of the city's roofs, siding and windows date to the rebuild after the March 1998 tornado, so they are now 25-plus years old and get dated precisely. River-valley lots get the flood-history and sump read, and Nicollet County's Radon Zone 1 standing puts a 48-hour test on most visits.
Is E. coli in well water dangerous?
It can be. CDC says most E. coli is harmless but some types cause serious illness, and a standard lab test does not identify the dangerous types. Because a positive result points to fecal contamination, treat the water as unsafe to drink until the well is disinfected and retested negative.
What are VOCs in well water?
VOCs, or volatile organic compounds, are a group of organic chemicals found in products such as paints, solvents, pesticides, and petroleum products. EPA notes they can reach private wells through waste disposal, spills, and runoff. A laboratory test is the only way to find out whether any are in your well.
Who is allowed to seal a well in Minnesota?
Only licensed or registered contractors. Minnesota Rules 4725.3875 makes the property owner responsible for having a contractor licensed or registered under the rules seal an unused well or boring. The Department of Health also states that only a licensed well contractor can legally seal wells. Its online directory lists currently licensed contractors. Sealing is licensed work done by a well contractor; testing the well in use is a separate step.
How can I tell if there is a forgotten well on my property?
The Department of Health suggests looking for a pipe 1 to 8 inches wide at, above, or below the surface, a low spot or sunken area, a metal, wood, or concrete cover, a windmill or old well house, and a concrete patch or glass block in a basement step or floor. Well pits and basement offsets are other common signs. Visible signs like these are worth raising with your agent and a licensed well contractor.
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