In the title compound, {(C4H16N3)[La(SO4)3(H2O)]}n, the La atom adopts an irregular LaO9 coordination geometry, including one bonded water molecule. The three sulfate groups adopt both monodentate and bidentate coordination to the metal ions. Two of the sulfate groups serve as bridges in the (100) and (010) directions, yielding infinite sheets, whereas the third is pendant to one La3+ cation. The protonated organic species interacts with the layers by way of N—H⋯O hydrogen bonds, and O–H⋯O hydrogen bonds involving aqua ligands also occur