This paper addresses the design of a reliable control system for a linear, asymptotically stable plant. Specifically, the considered problem consists of finding a regulator which, besides guaranteeing closed loop asymptotic stability and zero error regulation when all the instrumentation is in operation, also ensures that these properties are preserved, at their maximum possible extent, when some sensors and/or actuators faults occur, that is, some of the feedback loops open. Thus, a single regulator has to be found, able to contemporarily solve a certain number of classical regulator problems. Referring to a fully decentralized control structure, the paper presents a constructive necessary and sufficient condition for the problem to admit a solution when the exogenous signals are polynomial in time.