Do you know what temp your water heater thermostat should be set at for optimum performance? Do you know what yours is set at currently?
120°F is what is recommended by the Dept of Energy.
It's worth checking yours out as a lot of manufacturers set it to 140°F as a standard, which means wasted energy you pay for to heat up water hotter than you need it to be! So you can save $ along with saving your skin!