In the title hydrated molecular salt, C22H25N2 +·C6H4FO3S−·H2O, the cation displays whole mol­ecule disorder over two sets of sites in a 0.780 (5):0.220 (5) ratio. The quinolinium ring system is essentially planar, with r.m.s. deviations of 0.0162 and 0.0381 Å for the major and minor disorder components, respectively. The dihedral angles between the mean plane of the quinolinium ring system and the benzene ring are 5.1 (3) and 7.7 (11)°, respectively, for the major and minor components in the cation. In the crystal, cations, anions and water mol­ecules are linked into chains along [010] by O—H⋯O hydrogen bonds and are further connected into a three-dimensional network by weak C—H⋯O and C—H⋯F inter­actions. In addition, π–π inter­actions with centroid–centroid distances of 3.634 (3), 3.702 (5) and 3.838 (5) Å are observed.