Water conservation and appliance efficiency standards programs in the United States encounter challenges in assessing their economic impacts due to the limited availability of representative water and wastewater price data. In this report, we review water and sewage price and price trend data from two established sources: the Water and Sewerage Consumer Price Index from the U.S. Bureau of Labor Statistics and water and wastewater rate survey data from Raftelis/American Water Works Association (AWWA). By leveraging historical Raftelis/AWWA data, we develop an empirical approach to (1) interpolate the data by establishing regional trends that capture the pace of price increases as transparently and consistently as possible, and (2) extrapolate prices for future years for the purpose of quantifying water cost savings resulting from policy decisions. Additionally, our prediction models offer a means to verify data consistency when new rate survey data from Raftelis/AWWA become available.