A copper pipe at the exterior wall (the one that usually doesn't seem to do anything at all) has been dripping hot water? Well, that copper pipe actually is the drain line for the temperature-and-pressure relief on your water heater. A steady drip means that the valve is open, which means that you have one of three problems:

1) The water pressure in the house is too high.

2) The thermostat on your water heater is turned up too high.

3) The thermostat is broken.

Ask around the house to find out whether anyone has been adjusting the water temperature or pressure. If not, chances are you've got a bad thermostat.

And that's the On The House tip for today.