Experimental data of densities and viscosities are presented for 1-ethyl-3-methylimidazolium tetrafluoroborate + H2O binary systems over the entire range of their compositions at (293.15, 298.15, 303.15, 308.15, 313.15, 318.15, and 323.15) K. Excess molar volumes V-E and viscosity deviations Deltaeta have been obtained and fitted to the Redlich-Kister equation. The results show that the densities and viscosities are dependent strongly on water content and weakly on temperature. Comparatively, the viscosity deviation Deltaeta is more sensitive to temperature than the excess molar volume V-E.