Major task of cover systems for landfills and contaminated sites is the long-term minimization of water infiltrating into the waste body or the contaminated site under the climate of the particular location. Climate change will affect the water balance and effectiveness of cover systems. For assessing this impact in Germany, simulations were run with the water balance models BOWAHALD and HELP 3.95 D for 17 locations all over Germany and three 30-years periods, called present (1981-2010), near future (2021-2050), and far future (2071-2100), respectively. For the present weather data of the German Weather Service (DWD) were used and for the future periods projected data according to the global IPCC scenario A1B and the regional climate model WETTREG2010. Precipitation is projected to decrease from present to far future. Simulations of a standard landfill cover system for municipal waste and 17 locations in Germany resulted in increasing potential evapotranspiration, almost unchanging to slightly decreasing actual evapotranspiration and decrasing discharges (surface runoff, lateral drainage, and liner leakage). Simulations of a 2 m thick restoration layer with deciduous forest at the vulnerable location Dresden resulted in decreasing water content in the evaporative zone especially from near to far future and in significantly increasing drought stress. Planting drought stress tolerant vegetation in time is essential at such locations.