Abstract
In the title molecule, C19H20N2O4 center dot H2O, the benzimidazole ring system is essentially planar [maximum deviation = 0.013 (11) angstrom] and is inclined to the 4-methoxyphenyl ring by 30.98 (5)degrees. In the crystal, O-H center dot center dot center dot O and O-H center dot center dot center dot N hydrogen bonds involving the water molecule link neighbouring molecules, forming a two-dimensional network lying parallel to the bc plane. There are also C-H center dot center dot center dot pi and pi-pi interactions present. The latter involve inversion-related benzimidazole rings with centroid-centroid distances of 3.5552 (8) and 3.7466 (8) angstrom.