Arsenic occurs naturally in soil and minerals and is commonly found in groundwater throughout much of Minnesota. The occurrence and distribution of arsenic in groundwater is difficult to predict. Research is steadily increasing our understanding of the mechanisms and geologic conditions that determine arsenic occurrence in groundwater. The arsenic concentration in a new well, measured at the time of construction, is sometimes higher or lower, compared to subsequent sampling results.
Approximately 70 percent of all Minnesotans rely on groundwater as their primary source of drinking water. Wells used for drinking water must be properly sealed when removed from service to protect both public health and Minnesota’s invaluable groundwater resources. The Minnesota Department of Health with the assistance of the Board of Water and Soil Resources protects both public health and groundwater by assuring the proper sealing of unused wells.”