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
Bacterial cold water disease eggs. Bacterial cold water disease Bacterial cold water disease (BCWD) is a bacterial disease of salmonid fish. It is caused by "Flavobacterium psychrophilum" (previously classified in the genus "Cytophaga"), a gram-negative rod-shaped bacterium of the family Flavobacteriaceae. The disease typically occurs at temperatures below 13⁰C, and it can be seen in any area with water temperatures consistently below 15⁰C. Salmon are the most commonly affected species. This disease is not zoonotic. Asymptomatic carrier fish and contaminated water provide reservoirs for disease. Transmission is mainly horizontal, but vertical transmission can also occur. BCWD may be referred to by a number of