“Why is water dripping from the discharge tube of my water heater?” This tube is located on the outside of the water heater down line from the temperature pressure relief valve. This is also known as the TPR valve, pop off valve or relief valve. The TPR valve is usually mounted on top of the tank but sometimes it is mounted on the side. These valves can begin to drip water for two reasons. One the pressure in the tank is exceeding the set point on the TPR valve or the valve itself has become defected. As water is being heated in a closed container, (water heater), the heated water molecules expand causing pressure to build in the tank. When pressure builds above the pre-set pressure of the TPR valve, (about 120 psi), the valve will open and allow pressure to escape. So one reason for water discharge is that the TPR valve is equalizing internal pressure. However, no homeowner wants to deal with wet floors and possible mold issues. The solution for this particular problem is to install an expansion tank in the cold water line between the back flow valve and the water heater. These small tanks give the extra “expanded” water a place to go which stops the water dripping from the discharge tube.
The second reason for water leaking from the discharge tube is not related to pressure but a defective valve. As the valve gets older the seat sometimes cracks or a particle from the tank gets stuck in the seat holding it partially open. Either one of these problems will cause dripping from the discharge tube. A qualified plumber will be able to correctly diagnose and repair your dripping discharge tube.
