A liquid tank is provided for a heavy vehicle, suitable for fastening to a vehicle frame by at least one supporting bracket having shaped surfaces arranged for load bearing and locating contact against the liquid tank. The tank includes two end face portions and a shell portion with a non-symmetrical cross-section extending there between. The tank includes a first, shaped portion facing the vehicle frame, arranged for load bearing contact against a first shaped surface of the supporting bracket, a second, shaped portion extending partially below the frame, arranged to locate the tank relative to a second shaped surface of the supporting bracket, and a third, substantially rectangular portion facing away from the vehicle frame, and that the tank is fastened to the bracket by at least one clamping means. A bracket for supporting such a tank is also disclosed.