The Environmental Protection Agency (EPA) Clean Water Indian Set-Aside (CWISA) Grant Program and the Drinking Water Infrastructure Grant Tribal Set-Aside (DWIG-TSA) Program provide funding for wastewater infrastructure and drinking water infrastructure to American Indian tribes and Alaska Native (AI/AN) Villages. EPA coordinates with Indian Health Service (IHS) on these programs. Through this program evaluation, EPA sought to determine the extent to which the combined efforts of the EPA DWIG-TSA program and the EPA CWISA program have resulted in increased access to safe drinking water and sanitation facilities and in increased compliance with the Safe Drinking Water Act (SDWA) in Indian country. EPA also sought to better understand and explain how these programs are implemented, how implementation influences program performance toward their goals, as tracked by each programs strategic measures, and whether these measures are accurate indicators of each programs progress. In addition, because IHS often oversees and directly implements the infrastructure projects, EPA hoped to gain a deeper understanding of its own scope of influence and if and how EPA could better demonstrate program results. The evaluation looked at DWIG-TSA and CWISA program activities and influence since 2003.