Off-roading is a favourite recreation of many Australians, and Recreational Vehicles (RVs) or SUVs or 4Wds are they are variously known are a familiar sight on outback roads especially in autumn, winter and spring months. Because of the hot and/or dry conditions encountered in the Australian outback, planning a trip in a 4WD means that carrying adequate water must be a priority. Estimate that each person will need 2 litres of drinking water per day PLUS extra water for cooking, cleaning, washing, first aid and any other needs. When choosing water tanks, therefore always allow enough storage to provide each vehicle occupant with at least 5 litres of water per day, plus 20 litres extra for those unforeseen circumstances such as accidents, illness or breakdowns. Most people carry at least a 60 litre tank, with a couple of plastic jerry cans as backup. Stainless steel and polyethylene tanks are good materials to choose for your tanks. 4WD tanks may be subject to even more space restrictions than caravan water tanks, and the type of tank chosen can depend on the type of vehicle. Utes or utilities and trucks can have a water tank mounted either inside or outside the tray, while a wagon might have a slimline water tank mounted on roof racks, or a floor tray tank as in the illustration below, designed to fit over the transmission hump on the floor behind the front seats.