Recent climate changes mentioned in the Intergovernmental Panel for Climate Change (IPCC, 2013) report highlight the fact that in the past 50 years at the planetary level have occurred major changes in all climate components. In this regard the analysis of rainfall oscillations and of their impact on the hydric regime is particularly important, being witnessed in the surface and groundwater level variations. In the Suha River Basin, the year 2006 has been characterized by large rainfall quantities that have been generated, in particular, in June by persistent retrograde cyclonic activity (223 mm at Slătioara 3 hydrometric station, 269.1 mm at Gemenea 5 station, 271.6 mm at Valea lui Ion station and 351.8 mm at Stulpicani). On the main course of Suha, but especially on its tributaries (Gemenea and Slătioara) have been recorded very high flow rates (5% and 2% insurance) caused by the amounts of rainfall felt in a short time. To estimate the impact of rainfall on the Suha basin hydrological regime we used data collected by the Siret Basin Water Administration-Bacau, being analyzed the rainfall quantities, duration, intensity, tendency and effects.