A drinking water supply system for use in vehicles equipped with air conditioning comprises a reservoir for receiving a quantity of potable water and a pump for supplying water from the reservoir. A conduit extends from the pump to a valve situated in the passenger compartment of the vehicle and adapted to regulate water flow from the pump. The conduit extending from the pump to the valve includes a wide, flat portion which is wrapped around a section of the conduit of the air conditioning system of the vehicle that is maintained in a low temperature condition during operation of the air conditioning system. In this manner the water flowing through the drinking water supply system is cooled by heat transfer to the refrigerant of the air conditioning system.

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