Abstract: A reverse osmosis system including a high pressure pump and pump motor is enclosed in an unvented enclosure to reduce the amount of noise which would otherwise be transmitted into the surrounding environment. The pump motor is cooled by the flow of inlet water through heat-conducting tubing arranged as by wrapping to be in thermal contact with the pump motor. The absorption of thermal energy by the inlet water provides an additional benefit in that product water flow during reverse osmosis is a function of temperature, with the higher temperature water yielding an increased product water flow. In a preferred embodiment of the present invention, the tubing coil is secured to the pump motor housing by a clamshell-like clamping assembly. The purity of the product water is monitored by a conductivity cell including first and second electrodes arranged to detect the conductivity of the water.