toilet pipe rattle after flush

Fizz

in 1st floor bathroom. I've tried shutting valve after flush which reduced it after turning-on at low flow, but returns on flush. There is a Watts pressure reducing valve on water-line, was thinking it may have to do with pressure. Any thoughts?

Jamie Hall

A rattle -- not a water hammer -- is usually a pipe slightly loose in a hanger somewhere. Flush valves can cause an almighty water hammer in some cases, and that's best taken care of by a water hammer arrestor being fitted to the pipe. But a rattle? On a plain vanilla toiler? I'd look for a loose hanger.

Fizz

Thanks Jamie!

Fizz

Checked pipe in cellar, it was pvc supply rattling against waste pvc, shoved old towel up between, problem solved!

Alan (California Radiant) Forbes

Way to go Jamie & Fizz!

HomerJSmith

The Watts PRV is a logical assumption. I would check it with hose bibb pressure gauge to see what the house pressure is and see it there is in fact a pressure fluctuation when the toilet is flushed. A pressure fluctuation may be because of a faulty sticking PRV or tank fill valve. The fact that you have a PRV indicate that the street pressure is higher than desired. 55 to 65 psi is an optimal pressure for a residence.

If this is a problem with only one toilet I would probably suspect the toilet tank fill valve.

Fizz

Thanks Homer! Sounds logical