Expansion Tank FAQs

What is the purpose of expansion tank?

When water is heated it expands. In a closed piping system the expanding water will cause the pressure to increase. An expansion tank is designed to absorb this pressure increase to protect piping and plumbing fixtures.

Is an expansion tank necessary?

In a closed piping system the answer is yes. A closed piping system is indicated when there is a pressure reducing valve, a check valve or a backflow preventer installed on the water supply  piping.

How do I know if my expansion tank is working?

Here is a non-scientific, quick way to check your expansion tank:

• Find the shrader valve on the expansion tank. It is usually covered by a protective plastic cap.
• Remove the cap to reveal a shrader valve (like you would find on a bicycle or automobile tire).
• Carefully push on the center of the valve with a narrow object like a ball point pen to release just a spritz of air. If air come out the tank is most likely good. If nothing comes out or if water comes out it needs to be replaced.

How much does it cost to replace an expansion tank?

Expect to spend between $200 and $300.