I once had diagnosed a bad voltage drain and took it to a friend who is a whiz at electrical troubleshooting. He strongly suggested that I turn off the dome light.
I once drained a water heater to change out the heater element. After the longest time, I couldn't believe how much that tank held. Then I turned off the water supply to the tank. I don't know how much of the local reservoir I drained, but the City never called.
