Making use of the linearity of the equations which govern the problem, it is shown that the global constitutive behaviour of a linear poroelastic system, expressed within the formalism of hydraulical and mechanical loading parameters, is of the poroviscoelastic type, involving creep and relaxation functions between those parameters. It follows, in particular, \(0^\circ\) that the generalized strain variables of the system may be split into an elastic part associated with the undrained loading, and a viscous component corresponding to the delayed response. These notions are illustrated on the classical problem of one-dimensional consolidation, for which explicit forms of the creep functions are given.