General Purpose Centrifugal Pump End Suction Centrifugal Pump The Rule General Purpose Pump is designed for use as a washdown pump and/or to circulate water to your livewell tank(s). Heavy duty construction for use on commercial or pleasure boats. 1-1/2" (38mm) inlet and 1-1/2" (38mm) discharge outlet. The Rule General Purpose Pump must be mounted below the waterline. It does not deliver high pressure, nor is it self priming. It delivers lots of water but at low pressure. 12 volts DC unless noted.