An algorithm has been developed to determine the effectiveness in reducing water use by the implementation of a variety of water conservation measures. The algorithm developed may be used to estimate water use reductions resulting from the implementation of a large number of conservation measures and combinations of measures, and is designed so that it may be easily programmed as a new module within the Methodology for Areawide Planning Studies (MAPS) computer program. The effectiveness of any water conservation program is dependent upon site-specific conditions, so caution should be used in applying the numerical values for reduction, coverage, and interaction factors presented in this report. To serve this purpose, detailed references are given so that the user can utilize the sources of data to ensure that the values selected are appropriate.