The crystal structure of the title compound, (C(5)H(14)N(2))[ZnCl(4)]·0.5H(2)O, is built up from discrete 1-methyl-piperazine-diium cations with chair conformation, tetrahedral tetrachloridozincate anions and uncoordinated solvent water mol-ecules linked together by three types of inter-molecular hydrogen bonds, viz. N-H⋯Cl, N-H⋯O and O-H⋯Cl.