If you find a water pressure regulator on the property, do you automatically call for an expansion tank at the water heater if one is not present?
In all the states where I’ve worked in real estate, I’ve only found one expansion tank on a water heater, and that was here in San Diego back in 2002 or so.
I recently met a home inspector in Washington who always calls for an expansion tank if one is not present and there is a pressure regulator on the property.
Haven’t heard of this requirement before and cannot find such a requirement in any of my books at the moment.
Thanks for the guidance.
I’ll also try to check with some plumbers here later today.
The existence of a regulator does not automatically make it a requirement. It’s a bit more complicated than that.
608.3 continued. . .
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.
If your relief valve setting (whether on the heater or supply) is 150 psi (example) and your street/supply pressure exceeds 150 psi, the expansion tank is just a means to prevent opening of the relief valve when the system is closed - i.e. no water running.
Even with regulators, a closed system can gradually build up pressure equal to supply pressure. Eventually, even with an expansion tank, the relief valve will open if the system remains closed.
I think they’re trying to sell you and expansion tank :mrgreen:
Like you, I have see exactly 1 expansion tank during my career as a Home Inspector.
I don’t think they’re a bad idea, but until I get some definitive information that shows me the great benefit of having one, I will not be recommending their installation on a standard residential system. Also, the methods for determining their necessity, are well beyond our normal scope.
The scenario does not occur much here, so I have not seen a bunch either. Expansion tanks here are not needed unless your next door to the pumping station and then a pressure relief is required at the pressure reducing valve. A backflow preventer is only required if you have a residential fire suppression system or an irrigation system (around here). Of course, special circumstances demand a judgement call by the AHJ.
From what I’ve seen in the last 2 years you could ask 12 AHJ’s and get 12 different answers. You could even ask 2 different code inspectors in the same AHJ and get 2 different answers.