[masraum]

The "standard" is 140° on every water heater that I've ever seen/had, but anything that you read on energy efficiency says that they should be set to 120°.

In the summer when ground water is warm I have reduced the temp of the water heater. In the winter when the ground water is cold the heater goes back up. Butt even then I usually sick to 130-140°.

For you folks wondering how ground water temp impacts things, we used to live in an apt where the shower mixer valve was moderate and limited the shower temp too much.