An eyewash fountain and nozzle structure therefor that are especially useful in industrial and laboratory environments to provide a water discharge suitable for flooding the eyes of a workman to flush irritants and injurious matter therefrom. Use of such fountains is mostly sporadic and occasional so that water is ordinarily absent from the nozzle structure and supply conduit leading thereto at the start of each use either because of evaporation therefrom or, in the case of a freeze-proof fountain, because of the self-draining characteristics thereof. The fountain has a flow control device interposed in the water flow circuit to maintain the volumetric flow of water to the nozzle structure relatively independent of supply line pressure and to prevent surging of the water discharge from the nozzle structure. The nozzle structure has a large chamber provided with spaced apart inlet and outlet openings, and a diffuser interposed between such openings in alignment wtth the inlet intercepts any stream of water injected into the chamber to reduce its momentum and convert the discharge of water through the outlet into a lower-energy reduced-velocity flow.