• 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.

    Unsure where your drinking water comes from?

    Pie chart depicting Michigan resident's drinking water sources: 75% public, 25% private

    If you receive a water bill, your water comes from a public water supply.  If you do not pay for your water, you are on a private well. Approximately 75% of Michigan residents get water from a public water supply. Approximately 25% are on private wells.

    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.