We apply a monthly water-balance model (MWBM) to simulate components of the water balance for the period 1950-2099 under RCP4.5 and RCP8.5 for the Contiguous United States. We use the statistically downscaled MACAv2-METDATA temperature and precipitation data from 20 General Circulation Models (GCMs) from the Climate Model Intercomparison Program Phase 5 (CMIP5) as input to the water balance model. This dataset supports the USGS National Climate Change Viewer. The statistically downscaled dataset is: MACAv2-METDATA: Multivariate Adaptive Constructed Analogs (Abatzoglou & Brown, 2012, bias corrected by METDATA, Abatzoglou, 2013) Users interested in the downscaled temperature and precipitation files are referred to the dataset home page: MACAv2-METDATA: http://maca.northwestknowledge.net The 20 included GCMs are: bcc-csm1-1-m, bcc-csm1-1, BNU-ESM, CanESM2, CCSM4, CNRM-CM5, CSIRO-Mk3-6-0, GFDL-ESM2G, GFDL-ESM2M, HadGEM2 CC365, HadGEM2-ES365, inmcm4,IPSL-CM5A-LR, IPSL CM5A-MR, IPSL-CM5B-LR, MIROC5, MIROC-ESM, MIROC ESM CHEM, MRI-CGCM3, NorESM1-M