A method and an apparatus is described for preventing bacteria proliferation in a bottom end of a water holding tank of an electric water heater. Different water convection devices are described for convecting heated water from inside the tank and into the bottom end of the tank to raise the temperature at the bottom end sufficiently high to prevent bacteria growth and particularly at a temperature of at least 46 degrees C. where the Legionella bacteria can not survive. The temperature at the bottom end of the tank is monitored and the convection devices controlled to maintain the desired hot water temperature. An added benefit of the invention is that it also prevents sediment deposits and water temperature stratification in the tank bottom end section.