This paper presents a methodology to evaluate the admissibility of actuator fault configurations (AFC) when Linear Constrained Model Predictive Control (LCMPC) is used. The methodology combines the use of structural and feasability analysis. Structural analysis allows to evaluate the loss of reachability after a fault occurrence. The results of the structural analysis can be complemented with the feasibility analysis of the MPC problem taking into account the effect of actuator constraints after the fault occurrence. Additionally, a degradation analysis of the system performance can also be included. The proposed methodology is tested in the Barcelona water network.