Water supply contamination is the introduction of point and non-point source pollutants into public ground water and or surface water supplies.  Although minimal, water supply contamination does pose a threat to the county.

The causes of water contamination are numerous and range from failing septic systems, leaking underground tanks, to improper use of household chemicals. Residences near lakes and rivers often have wells that use shallow ground water that is particularly at risk for contamination. Seasonal homes or cottages may have older wells that need repair or replacement, but are a lower priority than the primary residence.

In some instances surface water is used for the household water supply.  Surface water presents a different set of risks and problems; information about special consideration and testing for surface water is available from the MN Department of Health (MDH).

The most obvious concern about an unsafe water supply is the health risk to family or guests. Wastewater contamination serves as a source of bacteria, viruses, and parasites that can cause gastrointestinal problems or transmit contagious diseases.

History

Residents in St. Louis County connected to municipal systems use Lake Superior as their primary source for drinking water in the Duluth area. Residents in the Iron Range Communities and northern St. Louis County rely either on groundwater and in some cases on a surface water source.  No records were found of any significant drinking water contamination incident.