Not the breaker switch on the wall panel,
But the little red button behind the screw on panel
Behind the insulation.

Not a huge inconvenience,
And not mine,
It's the apt. Owners water heater.
8 years old
But
The water here is heavy with lime and calcium

sounds like time to report it and let them sort it out, time to fix the thing up!

Thermostat, heating element
or the reset switch
itself...one of these is
failing.

Electrodes / heating elements need to be replaced and are on their way out. Easy and cheap to do.

Thanks,
It's a new reset switch.

They never schedule their plumber to replace the anodes.