A mop assembly is provided to uniformly and controllably apply and distribute liquids to the surfaces of exposed floors. A tank having a teardrop shape in the transverse plane maintains a low center of gravity and a relatively thin cross-section which along with the handle passing centrally through the tank permits the mop assembly to be used under low obstructions. Clamps around shouldered openings at either end of the tank through which the handle passes seal the tank. A control rod inside a sleeve passing through the tank permits operation of a control valve on a discharge port at the bottom of the tank. One head attachable to the mop assembly consists of a plate to which a porous pad is attached. The liquid is fed through tubing connected to the discharge port to dispense liquid through the pad. Another head consists of an elongated plate having an attached fiberous pad and a liquid distribution header which has a multiplicity of holes along one edge. A resilient connection secured between the head and the handle biases the head to fully contact the floor.