The problem of irregularity in climate variability has been identified as one of the major issues causing negative impacts on water resources over the last few decades. The purpose of this research is to demonstrate the presence of climate variability in the Souk-Ahras region and to comprehend its impact on water resources. This study region suffers from the absence of statistical studies on the basis of which structural and non-structural protection measures are sized. Various data and methods (reduced centered, Hanning 2nd order low-pass filter, rank correlation test, test Pettit, segmentation procedure, and drying coefficients) were used to accomplish this. When the reduced centred indices were applied to the pluviometric and hydrological series, they revealed a climatic variability characterized by an alternation of wet, normal, and dry phases. Statistical methods reveal breaks in the 1980s and 1990s, indicating a change in the rainfall and hydrological regimes. Over the course of the study, these breaks are accompanied by a 33% decrease in precipitation. However, with the resumption of the wet pluviometric phase of 1999-2007, the flow of the River Medjerda becomes surplus, resulting in a rapid recharge of the water tables of the order of 23% due to the drying coefficient. This is reflected in the upward trend in rainfall amounts greater than 20 mm (considered heavy rains), which appears to be resuming after a period of break. Precipitation and flow in the Souk-Ahras region are still low, and water tables are sensitive to changes in precipitation. These results are important data from a hydrological and agronomic point of view, especially in the modeling of soil moisture variations, runoff and irrigation.