Many US municipalities confront serious challenges due to aging water and wastewater infrastructure. Many systems require immediate repairs, upgrades, and replacement, but available funding is scarce. Readily available low‐interest financing is of great help to such municipalities. The Water Infrastructure Finance and Innovation Act (WIFIA) approved by Congress in 2014 was a step in that direction. WIFIA is a five‐year pilot program focused on supporting large‐scale projects that may be under‐served by existing state revolving funds (SRFs). The authors examine the structure and implementation of WIFIA and its impact on existing financing mechanisms. The cost of debt service in four representative communities in New York was compared under WIFIA, SRFs, and tax‐exempt municipal bonds. Although WIFIA financing offered the lowest debt service cost, savings from WIFIA depended on the spread between US Treasury rates and borrowing rates of the SRF‐administering agency.