Turn off power to the water heater at the breaker, or set the gas control to pilot/off if it is gas
Locate the thermostat control on the water heater
Remove the access panel if needed
Use a flathead screwdriver or your hand to adjust the temperature dial upward
Set the temperature to about 120°F to 125°F
Replace the access panel if removed
Restore power or relight the pilot if applicable
Wait several hours for the water to heat
Test the hot water at a faucet
If the water is still not hot enough, adjust the thermostat slightly higher and recheck
Do not set the temperature too high to reduce scald risk