Growling noise when shut off water or flush toilet.

Growling sound when shutting off a water facet or flushing toilet. Also shutting off outside facet causes the same thing. City has backflow preventer on incoming water line and I have installed an expansion tank. When expansion tank installed, Plummer inflated to ~ 55 psi and no noise or growling for several years. Now whenever toilet or outside valve closed I get the growling noise as the water shuts off. What can be the cause of this growling noise? Has the expansion tank psi dropped, outside water pressure increased so that I now receive this growling? Do I need to reduce the psi in the expansion tank?

MLogan
Smyrna, TN

 

Expansion tank may have a leak. There should be a schrader valve give it a quick push and see if water comes out.

 

I removed the cap and tried the valve but no water came out, just a little air. I measured the psi and have 50 psi. Should I have 60 psi?

MLogan
Smyrna, TN

 

Plumbers should be in later. What is making noise? Are the pipes rattling?

 

There maybe a problem with the pressure reducing valve. You need to check the house water pressure to see where it's at. You can use an inexpensive gauge to measure it.

3/4 in. Plastic Water Pressure Test Gauge- The Home Depot