Of course. The likely scenario is that the water tank has a preset range of acceptable temperatures and uses demand forecast information to decide whether to heat to the upper end of the range or let it cool to the lower end. Nobody suggests that we let them cool to unsafe temperatures.

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DoctorOetker a day ago | parent [-]

I'm not saying its impossible to achieve technically, just that there is a whole fleet of installed equipment and the comment I responded to made no mention of unsafe temperatures...

	▲	cogman10 16 hours ago \| parent [-]
		Unsafe temperatures happen at 42C. Pasteurization starts at 50C. A water heater that stays in the 60 to 55C range I mentioned never leaves the safe zone. But further, once pasteurization has occurred (which takes 2 minutes at 60C), Abiogenesis doesn't happen. A water heater can safely go down to 36C after it's hit that 60C temperature. Not that it would. So long as your water heater is hitting 60C once a day and stays above 42C, you have very little risk of developing dangerous levels of Legionella in the tank.