My static water pressure is high (140psi). When the water flows, the regulator can be adjusted (20 - 50 psi). When the water stops flowing, the pressure slowly builds back to 140 psi. IS THE REGULATOR BAD? (Watts 25 AUB). I am measuring at the CW laundry connection.

Sounds like a defective pressure reducing valve to me. Some regulators have a port for cleaning, some do not. May have debris preventing the valve from closing completely.

HI Mike...

It certainly seems so, huh? ;)

It could be that the regulator valve is slowly leaking by and these are super cheap/easy to replace overall so that would probably be the first place I would start.

With that being said, do you have a lawn sprinkler system with a check valve... could be closing the system off and not allowing for expansion in the hot water system?

How about a water softener or a whole house filter in the home... either could be plugged and allowing pressure to build.

Also, look for an expansion tank at the water heater... could be defective.

Thoughts..

Mark