In this paper, a fault detection and isolation algorithm together with a switching control strategy are used to solve the problem of a fault accommodation in the three tank process. The nonlinear model of the process is linearized through state feedback. Then, a PI and a state feedback controller are designed to insure some predefined control performances. The fault-tolerant control strategy is based on a online detection of faults and the selection of an adequate controller. The experimental results on a three tank benchmark are presented and discussed.