An improved motor-driven pump is provided for delivering a flow of water in a swimming pool or spa environment or the like. The improved pump includes a motor mounted within a motor housing having a seal plate mounted at one end thereof. The seal plate carries a shaft bearing for rotatably supporting a drive shaft having an outboard end connected to an impeller disposed within a pump chamber defined cooperatively by the seal plate and a volute housing mounted thereon. A primary seal assembly includes an axially spring-loaded dynamic seal ring carried on the drive shaft for rotation therewith and for running engagement with a stationary bushing carried by the seal plate. A secondary seal assembly is positioned axially between the primary seal assembly and motor bearing, and includes at least one slinger disk for radially outwardly slinging any water leaking past the primary seal assembly through a vent chamber.