This is an e-supplement to GAO-16-474. This e-supplement presents the results of GAO's web-based survey of 1,303 U.S. municipal water utilities. The survey asked questions about: (1) the technologies utilities use to improve water distribution efficiency; (2) the technologies they use to treat nontraditional water sources; (3) the challenges they face in using such technologies; and (4) the basic characteristics of their infrastructure, operations, and service area.