Do I Need a Thermal Expansion Tank?
As your water heater gets hot, the water inside begins to expand. This quick expansion can cause stress upon your plumbing. A thermal expansion tank, also known as a water heater expansion tank, is a great tool to help mitigate damage. These tanks will catch any overflow and prevent the water pressure from getting too high. It is attached to the water supply line (preferably on the cold line side) as a means of relief and stability.