The spray head for a pre-rinse assembly includes a discharge cover having a plurality of ports for discharging water and a diffuser within discharge cover having a circumferential wall with at least one slot for directing a jet of water onto the fins of a rotatable impeller within the diffuser. The impeller has a plurality of tabs disposed relative to the ports whereby a respective tab momentarily covers a respective port to prevent passage of water therethrough during rotation of said impeller thereby effecting a pulsating stream of water through a respective port.
