Nasicon-type phosphates Cu1-xHxZr2(PO4)(3) (0 < x < 1) and Cu1-xH2x-1Zr2(PO4)(3) (0.5 < x < 1) have been investigated by magnetic susceptibility and electron paramagnetic resonance (EPR). Room-temperature EPR spectra at X-band (9.5 GHz) exhibit relatively different local information about paramagnetic environments in the two sets. Analysis by computer simulations of Cu1-xHxZr2(PO4)(3) spectra reveals that Cu2+ ion is located in an axially distorted octahedron, which can be assigned to the M(1) site. However, in the case of Cu1-xH2x-1Zr2(PO4)(3), EPR parameters suggest that Cu2+ ions are distributed in two types of sites with axial and lower than axial symmetries; these latter can be attributed to M(1) and M(2) sites respectively, g and A components are related to structural properties using molecular orbital method. Data are obtained on variations of the bond covalence with the composition.