Public water supplies may be large, like the Great Lakes Water Authority, which serves 3.7 million residents, or they may be smaller, such as a supply serving a manufactured housing community. Some public water supplies get water from groundwater, some from surface waters (lakes or rivers) and some blend groundwater and surface water sources together. To ensure the drinking water for the largest portion of Michigan residents was tested for PFAS, beginning in April 2018, the Michigan Department of Environmental Quality (MDEQ) implemented a statewide program to test:
This sampling was completed in December 2018. Therefore, approximately 7.7 million of Michigan's 10 million residents have now had their drinking water tested for PFAS. The results of this testing are detailed in the interactive tables below. A summary report of the overall results is available to the right.
The MDEQ has provided recommendations based on PFAS levels. View this notification protocol (pdf).
The United States Environmental Protection Agency (USEPA) set a Lifetime Health Advisory (LHA) level for two PFAS in drinking water: perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) . The LHA level is 70 parts per trillion (ppt, equal to 70 ng/L) for PFOA and PFOS combined, or individually if only levels for other PFAS chemicals. The State of Michigan is using 70 ppt for decision making purposes.
Only two supplies were found to have PFOS+PFOA over the USEPA LHA: