Thermal Expansion Tank on Remodel?

I got one that stumped me today.

Replaced electrical water heaters in 2003 on a 1950’s home. Plumber stated that expansion tanks were not needed because of the type of meter valve at the street? It was a opened end system and not a closed system like newer homes, therefore did not need a thermal expansion tank?

Wow never heard of this. I hope I stated this well enough where it makes some sense to a plumbing guru…

Here’s what the UPC says. . .

608.3 In addition to the required pressure or combination pressure and temperature relief valve, an approved, listed expansion tank or other device designed for intermittent operation for thermal expansion control shall be installed whenever the building supply pressure is greater than the required relief valve pressure setting or when any device is installed that prevents pressure relief through the building supply. The tank or device shall be sized in accordance with the manufacturer’s recommendation.

Thanks for the reply Jeff. But I am not sure if this answers my question? Or does it?

Primarly with the type of water meter he stated that was installed at the street being a ‘‘open pressure system’’ versus a ‘‘closed pressure system’’ ?

This I never heard of. Is there in fact several or 2 different types of water meters/valves?

Or does a thermal expansion tank or device similar need to be installed regardless?

Expansion tanks are not “automatically” required on every residential system where a there is a heated storage tank. In fact, I rarely see expansion tanks installed.