the source of water coming into the airport;
2. the airport water system, which includes the on-site distribution system. It may also include treatment facilities if the airport produces its own potable water;
3. the transfer point (sometimes referred to as the watering point), including the water transfer and delivery system. It is typically a temporary interconnection between the hard plumbed distribution system of the airport (e.g. at a hydrant) and the aircraft water system, by means of potable water vehicles and carts, refillable containers or hoses. This
water transfer process provides multiple opportunities for the introduction of contaminants into the drinking-water;
4. the aircraft water system, which includes the water service panel, the filler neck of the
aircraft finished water storage tank and all finished water storage tanks, including
refillable containers/urns, piping, treatment equipment and plumbing fixtures within the
aircraft that supply water to passengers or crew.