A water transport vehicle is a vehicle used by a private water carter. If you intend to sell the water for any purpose connected with human consumption (such as preparation of food or ice, or to preserve unpackaged food) you will need this licence.
You will need to register your business with the council in which your vehicle is garaged (principal council), regardless of where you deliver the water. If you operate more than one vehicle then you need to register with the council in which the majority of vehicles are garaged.