Abstract: A self-cleaning siphon-type method for removing sludge from a water or liquid waste settling tank is disclosed. A siphon conduit, through which liquid flows from the settling tank into an adjacent chamber which contains liquid at a level lower than the level in the tank, is provided along with means for withdrawing liquid from the chamber at a constant, predetermined rate. Momentarily decreased flow through the siphon tube due to clogging the siphon conduit inlets results in a lowering of liquid in the chamber and increased suction in the conduit, which increased suction tends to unclog the siphon conduit inlets.