In the asymmetric unit of title coordination polymer, {(C(16)H(36)N)[Zn(3)(C(9)H(3)O(6))(2)(OH)]·0.25H(2)O}(n), there are three independent Zn(2+) cations, two benzene-1,3,5-tricarboxyl-ate ligands and a μ(3)-bridging hydroxide group, together with a tetra-n-butyl-ammonium counter-cation and a partially occupied water molecule of solvation (occupancy 0.25). Each Zn ion is coordinated by three carboxyl-ate O atoms and one O atom from the bridging hydroxide ion, displaying a slightly distorted tetra-hedral stereochemistry [overall Zn-O range = 1.875 (3)-1.987 (2) Å]. An intra-molecular hydrogen bond involving the hydroxide H atom and a carboxyl-ate O-atom acceptor is also present in the complex unit. The bridging benzene-1,3,5-tricarboxyl-ate anions generate a three-dimensional framework structure.