The title compound, C6H15N3簮5H2O, crystallizes in the high-symmetry trigonal space group P/bar{3}c1. This is, after more than 30 years of effort on this compound, the first reported structure of the free base of this macrocycle. Six N-H...O hydrogen bonds are formed between the water O atom occupying a special site at the origin and N atoms of six neighbouring 1,4,7-triazacyclononane molecules.