High elevation mountains often constitute water supplier to arid and semiarid adjacent areas. Indeed, a significant component of groundwater recharge to alluvial aquifer of basin floor potentially originates from mountain ranges and is known as Mountain Front Recharge. The latter may involve various processes (stream losses, subsurface flow from the mountain block, direct infiltration from rainfall, etc). In the Haouz-Tensift basin, central Morocco, the High-Atlas Mountains are often referred to as the water tower (600 mm as average precipitation) for the Haouz plain (precipitation of 250 mm). Groundwater recharge processes in the area are still poorly documented and need to be well understood and assessed for a better management of groundwater already experiencing severe depletion. To this objective, stable isotopes (18O and 2H) and major ions were used. Precipitation (rainfall and snow), wells, springs and streamflow were sampled in September 2017 (dry season) and March 2018 (wet season). Results have shown that in addition to streamflow losses and subsurface inflow from the mountain front, surface water leakage beneath irrigated crops contributed mainly to groundwater recharge. The irrigation practices and the traditional irrigation regime are likely to generate significant amounts of recharge to the alluvial aquifer of Haouz.