The title compounds, C15H19N4O+·Cl− and C15H19N4O+·Cl−·H2O, obtained in attempts to synthesize metal complexes using tetrahydroindazole as a ligand, were characterized by NMR, IR and X-ray diffraction techniques. The partially saturated ring in the tetrahydroindazole core adopts a sofa conformation. An intramolecular N—H⋯N hydrogen bond formed by the protonated amino group and the N atom of the pyridyl substituent is found in the first structure. In the hydrochloride, the organic moieties are linked by two N—H⋯Cl− hydrogen bonds, forming a C(4) graph-set. In the hydrate crystal, a Cl− anion and a water molecule assemble the moieties into infinite bands showing hydrogen-bond patterns with graph sets C(6), R64(12) and R42(8). Organic moieties form π–π stacked supramolecular structures running along the b axis in both structures.