The Water Resources Program is able to test your private well for common pollutants such as coliform bacteria, nitrates, and arsenic. If you are interested, contact Shane Bowe. If you have city water, contact the sanitation program.
If you are noticing a sulfuric (rotten egg) taste or odor to your water, this is commonly caused by sulfur bacteria in groundwater and in most cases is not harmful. There is a procedure to help reduce the odor called “shocking” your well with a strong chlorine solution. The Minnesota Department of Health provides guidelines here.