Catalyzes the dephosphorylation of histidinol-phosphate to histidinol, the direct precursor of histidine. H2O + L-histidinol phosphate = L-histidinol + phosphate Binds 1 Mg(2+) ion per subunit. Amino-acid biosynthesis; L-histidine biosynthesis; L-histidine from 5-phospho-alpha-D-ribose 1-diphosphate: step 8/9. Deletion mutant is histidine auxotroph. Complementation of the mutant with hisB from E.coli restored growth on M9 without added histidine. Belongs to the HAD-like hydrolase superfamily. SerB family.