The Contamination Investigation Unit assists local health departments in conducting drinking water quality investigations in areas of known or suspected environmental contamination. The Unit members provide assistance by advising local health department staff, and others conducting groundwater quality investigations, in the selection of drinking water locations sampled, types of analyses needed to be performed, and scheduling of Drinking Water Lab analysis. Staff members coordinate toxicological assessments of identified chemical exposure, assist in drafting of health advisory notices, and develop drinking water quality monitoring programs.

The Contamination Investigation Unit is also responsible for administering drinking water replacement activities under Part 201, Environmental Remediation, of the Natural Resources and Environmental Protection Act, 1994 PA 451, as amended (Act 451). Staff contract with local units of government to extend community water lines and well drillers to replace contaminated water wells. Provision of bottled water, installation of treatment devices, and well abandonment is also administered under the Contamination Investigation Unit's Part 201 program. Staff members have expertise in environmental health sciences, geological sciences, water chemistry, well construction, groundwater movement, and toxicology.