The pump and motor assembly of the suction vessel mounted pump is contained within a suction vessel built to the appropriate pressure vessel code for each application, making the installation safe, simple, and reliable. The suction vessel functions as the outer pump casing. It is fabricated with a suction nozzle, welded couplings (for drain and liquid level indication), support brackets, a head plate with discharge nozzle, a conduit for electrical cables, and a vent nozzle. The result is a compact, lightweight, uncomplicated installation having low noise levels and significant safety advantages over conventional pumps.