: A month ago water started flowing from the water heater relief value when the water was heating. I've heard rumors that I need a Thermal Expansion Tank. What is a Thermal expansion tank and why now do I suddenly need one. What is cost?

Tom,
Check water pressure in the home first. It should be below 80 PSI. Is the relief valve old? Could there be a check valve added at the water meter? Many of the new meters have check valves now.

If your Plumbing Code requires a Backflow preventer, Check Value or Pressure Reducing Valve, You will need an expansion tank.

• Therm-X-Trol