Water heating by a domestic water heater. Two conflicting safety issues affect water heater temperature—the risk of scalding from excessively hot water greater than , and the risk of incubating bacteria colonies, particularly "Legionella", in water that is not hot enough to kill them. Both risks are potentially life-threatening and are balanced by setting the water heater's thermostat to . The European Guidelines for Control and Prevention of Travel Associated Legionnaires’ Disease recommend that hot water should be stored at and distributed so that a temperature of at least and preferably is achieved within one minute at points of use. If there
Water supply and sanitation in Gibraltar was, perhaps not surprisingly, on the state of public health in the territory. The large numbers of water containers standing open across Gibraltar provided an ideal breeding habitat for mosquitoes. Ships carrying cargoes from Africa brought with them the tropical disease yellow fever, which is spread by female mosquitoes carrying the infection. From 1804, Gibraltar suffered five outbreaks of yellow fever; in the first and most devastating, the death toll amounted to 5,733 people out of a total of around 18,000, representing 32 per cent of the population. The second epidemic coincided with the arrival in 1814 of General Sir