Expansion Tank
Controls pressure changes created when water heats and expands inside the system, matched to licensed local plumbers who install and service them correctly.
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Why Your Water Heater Might Need an Expansion Tank
An expansion tank absorbs the extra pressure created when water heats up and expands inside a closed plumbing system, a common setup once a home has a check valve or pressure regulator installed. Without one, that extra pressure has nowhere to go, which can stress your water heater, pipes, and fixtures over time.
Water expands when it heats, and that pressure has to go somewhere, ideally into a tank built for it.
Signs You May Need an Expansion Tank
These situations often point to a missing or failing expansion tank.
- Your home has a check valve or pressure regulator on the main water line
- You’ve noticed banging or knocking pipes (water hammer) after hot water use
- The water heater’s pressure relief valve drips periodically
- A plumber has flagged closed-system pressure as a concern during another visit
- Your existing expansion tank feels waterlogged or isn’t holding air pressure
What to Check Before Requesting an Expansion Tank Quote
A quick check helps you describe the issue accurately.
- Tap your existing expansion tank, if you have one, it should sound hollow on top, not full of water
- Note whether your home has a check valve or pressure regulator installed
- Check if your water heater’s pressure relief valve is dripping
- Ask your plumber whether your system is ‘closed’ and needs an expansion tank as a result
Why Compare Quotes Instead of Calling Just One Plumber
Here’s what matters when comparing expansion tank quotes:
- Matched with licensed, insured plumbers who correctly size the tank for your water heater
- Compare pricing for installation or replacement of a waterlogged tank
- Free to use, with zero obligation to hire anyone you're matched with
An expansion tank is a small, inexpensive part that protects a much more expensive water heater. Comparing quotes takes just a few minutes.
Tell Us What You Need
Answer a few quick questions about your plumbing job — the problem, your timeline, and your property.
Get 3 Competing Quotes
We match you with up to 3 licensed, insured plumbers in your area who compete for your business.
Pick the Best Deal
Compare quotes side-by-side. Check pricing, warranties, and reviews, then choose the pro that fits your needs and budget.
Frequently Asked Questions
Do all homes need an expansion tank?
Not all, only homes with a closed plumbing system, typically created by a check valve or pressure regulator. A plumber can confirm your setup.
How do I know if my expansion tank has failed?
A waterlogged tank feels solid or heavy when tapped rather than hollow on top, and it stops effectively absorbing pressure.
Is a dripping pressure relief valve related to this?
Often yes, excess pressure with nowhere to go is a common reason the relief valve activates.
How long do expansion tanks typically last?
Around 5 to 10 years, depending on water quality and system pressure.
Is installing an expansion tank a big job?
No, it’s typically a quick installation, often under an hour for a straightforward setup.
Is comparing quotes free?
Yes, with no obligation to hire anyone you’re matched with.