For a long time, the drinking water supply to the Dakar region was provided by the Thiaroye boreholes. But the advance of the salt wedge has led the state authorities to order a halt to these drillings. This disconnection has not only led to a decrease in drinking water production in the area, but it has also encouraged the recurrence of flooding due to the rise of the water table. The objective of this work is to study the impact of infiltability on floods in Thiaroye. For the determination of infiltration capacity, the Horton model was used. The evolution of infiltration as a function of rainfall according to the wetness of sandy clay soils shows that the wetter the soil, the lower the infiltration, the greater the return time, the lower the infiltration for the same duration. The submersion time, which corresponds to the beginning of the runoff, arrives instantaneously after the onset of the downpour and after calculation, the value of the runoff is 14.16 mm on 30 mm rain; a runoff coefficient of 47.2%. The calculated runoff coefficients are around 0.50 and depend on the intensity and duration of the rainfall. Keywords: Infiltrability, Thiaroye, flow, humidity