the pump is a black cylindrical item below the reservoir, riding in a bent piece of sheetmetal. The sheetmetal has two holes for two "pips" on the plastic reservoir. Disconnect one water tube, pull off the electrical connector (two wires to a plug, only fits one way), and slide off the pump in the sheetmetal bit. Actually, you could to the pump without taking it off the reservoir, but it's awkward, and if your use a scrubby and some detergent, usually the reservoir will get clean enough to look almost-new.