Higher volume supplies of groundwater can be difficult to obtain in the northeast, compared to the central part of the state.
Groundwater is available throughout this region in volumes sufficient to satisfy residential use.
About 40 percent of the shallow wells (less than 30 feet deep) in the central region have higher nitrate concentrations than the EPA allows for drinking water.
Metro area and the southeast
Groundwater in the Twin Cities metro area shows high concentrations of chloride.
Though this region has multiple aquifers, groundwater availability is threatened by high consumption in the Twin Cities metro area.
Most of the sand and gravel aquifers in southern Minnesota have nitrate concentrations that exceed EPA guidelines for human health.
Western and southwestern Minnesota
About 20 percent of the monitored shallow wells in the southwestern region have higher nitrate concentrations than the EPA allows for drinking water.
How groundwater affects surface water
Groundwater contamination and shrinking water levels in the ground can affect bodies of water on the surface. Groundwater feeds surface waters and helps maintain water levels during droughts. If groundwater is being used up and the water level in a stream goes down as a result, the pollutants in the stream will be concentrated, doing greater environmental damage.
The low water levels in Little Rock Creek north of St. Cloud illustrate how groundwater interacts with surface water. Heavy groundwater pumping in the area causes the stream to shrink in the summer, killing off fish. Downstream at Little Rock Lake, low water causes massive summer algae blooms. The local soil and water conservation district is working with farmers on irrigation management strategies that will use less groundwater.