A pump assembly supportable in a tank having an opening includes a pump such as a grinder pump and a cover attachable to the pump. The cover has a peripherally-extending portion extending outwardly from the pump and the peripherally-extending portion is sized to rest on a first surface of the portion of the tank defining the opening. A quick-release latching mechanism may include a plurality of members such as arms or pawls which are movable generally radially between a retracted position wherein the outer ends of the plurality of members are disposed inwardly of the peripherally-extending portion of the cover allowing the pump assembly to be lowered into the opening in the tank, and an extended position wherein the outer ends of a plurality of members are positionable against a second opposite side of the portion of the tank defining the opening to compress the portion of the tank forming the opening between the cover and the plurality of members.