This study examines the economic impact of the Central Arizona Project (CAP) to the State of Arizona in two aspects: the construction of CAP, 1973‐1993; and the impact of CAP's water supply delivery operations, 1986‐2010. A modified IMPLAN input‐output model for the State of Arizona is used to implement both analyses. The economic impacts for each analysis are assessed in terms of gross state product (GSP) and employment.