Is the temperature rising and the pressure building? Is that innocuous-looking pipe that's been dormant for years suddenly coming to life -- with a steady drip, drip, drip? Don't panic yet. You've just entered 'the water- heater pressure zone.? To be sure, follow the pipe up to where you find a brass valve -- on top the water heater or on the side near the top. That's the temperature-and-pressure relief valve. It keeps things in check, but needs testing periodically for safety and operational efficiency. To do so, open and close the small lever to flush the valve. If this hasn't been done for a long time. it might drip. If it does, open and close it again, and monitor it for a day or two to be sure it quits. You can also tap it gently with a small hammer and reopen and close it a few times to reseat it. Should it ever open on its own, it signals a problem. That would indicate it's time to call in a pro. And that's the On The House tip for today.