Private Wells in Martin County, MN
Where the water comes from, what is in it, and why both answers matter for the pump that lifts it into your house.
Water from under the glacier's floor
The last glacier to cross this county, the Des Moines Lobe, melted back about 14,000 years ago and left the flat till plain Martin County farms today. Till is dense ground rock and clay, and it does not give up water easily. The wells here reach through it to buried layers of sand and gravel, old meltwater channels and outwash now sealed under the till. Drillers call them buried drift aquifers. Beneath everything sits Cretaceous bedrock, mostly shale and sandstone.
Those sand and gravel layers do not spread evenly under the county. One farm finds good water at one depth, the neighbor a different layer at another. That is why well depth, pump size, and replacement cost are per-well facts here. Minnesota's County Well Index holds logs for more than 599,000 wells and borings statewide, and most drilled wells have a record in it. Your well record shows the depth, the layers passed through, and the original pump setting.
What is in the water here
Farm-country groundwater carries a few regulars. None of this is a reason to fear a well. It is a reason to test one.
- Nitrate. The signature farm-belt concern, especially in shallower wells. At 2024 state agriculture department testing clinics, which included Martin County, 6 percent of more than 2,400 private wells sampled came in over the 10 mg/L federal limit. Infants under six months are the highest-risk group. MDH recommends testing every year.
- Arsenic. It occurs naturally in the Des Moines Lobe till. In an eight-county project area of southern Minnesota that includes Martin County, 16 percent of new private wells drilled since 2008 exceed the 10 microgram standard. Statewide the figure is about 11 percent. One test tells you where your well stands.
- Manganese. Southwestern Minnesota groundwater runs higher in manganese than most of the state, and high levels matter most for infants. It also stains fixtures and laundry.
- Iron and hardness. Mostly a nuisance rather than a health issue. Iron above 0.3 mg/L stains sinks orange and feeds iron bacteria. Hardness scales up water heaters and softener demand is a fact of life here.
MDH publishes a free Well Owner's Handbook, and the state agriculture department runs periodic free testing clinics in the county. Testing is cheap. Guessing is not.
Why water chemistry is a pump issue
Sediment, iron, and hard water act like grit inside a pump. They wear impellers, plug intake screens, and shorten the life of everything mechanical between the aquifer and your tap. A well that makes sandy or iron-heavy water replaces pumps more often, and it deserves a pro who sets the pump depth with that in mind. If your water changed lately, gray tint, sand in the aerators, new staining, that change is diagnostic. Mention it when you request a quote, because it shifts what the licensed contractor looks for first.
Who may legally work on a well in Minnesota
Minnesota licenses well contractors and pump installers through the Department of Health under state well law, chapter 103I. The law carves out one exception. A property owner may work on a well on land they own or lease for their own farm or home, and state notification requirements still apply to regulated work. For everyone else, hired well and pump work requires an MDH license. Any contractor we refer can be checked in the state directory in about a minute.