A spray assembly for a milk tank, where there is an elongate water pipe positioned in the tank, and a plurality of spray nozzle assemblies mounted to the pipe. Each spray nozzle assembly comprises a nozzle member having radially inwardly directed openings leading to a middle impact chamber which in turn leads directly to an upper discharge opening. The water flows radially inwardly to the impact chamber to provide a random expanding spray pattern that washes upwardly against the interior surface of the tank. The nozzle member is retained by a member having an expanded head and a shank that extends downwardly through a second opening in the pipe. A releasable retaining member retains the connecting member in place. In operation, the water flows against substantially all of the surface portions of the nozzle assembly to provide a self-cleaning action. The assembly can be easily disassembled for maintenance or possibly further cleaning.