The ³¹P chemical shift tensors were measured in the paraelectric (P) and ferroelectric (F) phases of PbHPO₄. They reflect the approximate C_2v and C₃ point symmetries of the ³¹P sites in the P and F phases of the crystal. The transition from C_2v to C₃ is the result of a proton ordering in double-well potentials below the phase transition temperature. In the P phase the width of the proton decoupled ³¹P-resonances is larger than in the F phase, and the orientation dependence of the excess width is clearly correlated with that of the ³¹P line splittings in the F phase. This finding is interpreted as giving evidence that the Pc-space-group symmetry of the F phase persists in the P phase. The authors believe that this is due to the presence of a homogeneous internal biasing field-produced by oriented defects with a nonzero charge and dipole moment-which breaks the symmetry of the high temperature phase in a similar way to an external electric field. The orientation of these defects is due to the fact that the crystal was grown in the ferroelectric phase.