One fine day, you walk past the water heater, and your foot gets wet. Hmm, that’s strange. You take a look and notice a very slow drip – drip – drip from the tube on the side of the water heater. That can’t be too bad. Just put a bucket under the tube to catch the water? Sorry, not a good idea.
That tube on the side of the water heater is the temperature and pressure relief (T and P) valve (also called TP and R valve). This valve monitors temperature and pressure inside the tank. If the temperature or pressure becomes too high, the valve will open to dump steam and water. This prevents excessive pressure from building and possibly rupturing the tank.
If you find a leak, this often means the valve is not seating properly, and perhaps debris has built up in the valve. It may also mean the temperature or pressure is too high.
When the T and P valve is leaking, have a plumber check for problems and replace the valve as needed. Don’t ignore this problem, as it could create a safety hazard.