The title compound, C(24)H(27)N(2)Si(+)·Br(-)·H(2)O, was synthesized from 1-(dimethyl-phenyl-silylmeth-yl)-1H-benzimidazole and (2-bromo-eth-yl)benzene in dimethyl-formamide. The benzimidazole ring system is nearly planar, with a maximum deviation of 0.015 (5) Å, and forms dihedral angles of 73.0 (3) and 39.6 (2)°, with the phenyl rings. In the crystal, mol-ecules are linked by O-H⋯Br, C-H⋯Br and C-H⋯O hydrogen bonds. In addition, the structure features π-π stacking inter-actions, with a face-to-face separation of 3.644 (3) Å between parallel benzimidazole ring systems.