Many public water systems are struggling to locate and replace lead pipes that distribute drinking water across the United States. This study investigates factors associated with customer participation in a voluntary lead service line (LSL) inspection and replacement program. It also uses quasi-experimental and experimental methods to evaluate the causal impacts of two grant programs that subsidized homeowner replacement costs on LSL program participation. LSLs were more prevalent in areas with a higher concentration of older housing stock, Black and Hispanic residents, renters, and lower property values. Owner-occupied and higher valued properties were more likely to participate in the LSL program. Results from the two grant program evaluations suggest that subsidies for low-income homeowners to cover LSL replacement costs can significantly boost participation, but only when the programs are well publicized and easy to access. Even then, there was still significant non-participation among properties with confirmed LSLs.