This paper presents a methodology for identifying an interconnected tanks system, that exhibit a nonlinear behavior, as a hybrid dynamic system (SDH). The identification is done, through a modified procedure for parametric identification of piecewise affine autoregressive exogenous (PWARX) models. This is an improvement of the classical bounded error approach. The tank hybrid system is represented in state variables in order to design a static output feedback control for switching systems. The aim is to find the existence of a switched quadratic Lyapunov function to check asymptotic stability of the switched system.