Are Expansion Tanks common?

[cbustaylor]

I've been a homeowner for 12 years, never had seen or heard of an expansion tank. Now I've got a work assignment that has me trying to learn more about them. One thing I'm really confused about is how many households have one. I read that in many places its code, but even in those areas I've talked to people who have no idea what one is and don't have one.

So in your area, what % of households do you think have an expansion tank? Really appreciate your comments.

 

[Reach4]

So in your area, what % of households do you think have an expansion tank? Really appreciate your comments.

It is going to vary by town and region. You need them if the water meter installs have a check valve (one-way valve), and you will need one (or an alternative pressure relief valve which releases water) if you have a pressure reducing valve. From what I can tell, PRVs are much more common in the western US.

People with wells have a pressure tank that would also serve a thermal expansion function, although the main purpose of their tanks is something else.

 

[Sponsor]

 

[Terry]

An expansion tank is for closed systems. When it became a worry that homes on public systems could have problems with cross contamination, water districts started installing water meters with check valves. Many "open" systems became "closed" systems overnight. For example, a home I had in Redmond, fairly old water heater yes, but failed soon after the water meter was replaced. Since this is a rather new code requirement, it's also new to homeowners. I do like having an expansion tank in the system though, as it cushions the ups and downs of the pressure in the home.