Drinking water regulations require public water supplies to maintain an inventory of service line materials in their distribution systems. By October 16, 2024, public water supplies were required to complete and submit a distribution system materials inventory (DSMI) to the Michigan Department of Environment, Great Lakes, and Energy (EGLE), which includes an inventory of all service lines and service line materials.
This provides important information for planning service line replacement efforts in communities with lead service lines or galvanized service lines that were previously connected to lead. This also allows water supplies to properly notify residents served by lead service lines, galvanized service lines that were previously connected to lead, or service lines of unknown material, of the potential risk for lead in their drinking water and ways they can reduce that risk.
Shown on this page is service line material summary information provided by water supplies in their DSMI.
(8%; 203,050) Lead: Any portion of the service line contains lead.
(2%; 61,608) Galvanized previously connected to lead (GPCL): A galvanized service line that was, or is presumed to have been, previously connected to lead.
(12%; 315,372) Lead status unknown: A service line where there is not enough information to classify it in one of the three categories above. Until additional information is obtained to say otherwise, it is possible these service lines could contain lead or GPCL.
(78%; 2,028,832) Non-lead: A service line that does not contain lead or GPCL. These lines could be made of copper, plastic, galvanized that was never connected to lead, or other material.