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toilet pipe rattle after flush

Fizz Member Posts: 547
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
    Jamie Hall Member Posts: 22,171
    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.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Fizz
    Fizz Member Posts: 547
    Thanks Jamie!
  • Fizz
    Fizz Member Posts: 547
    Checked pipe in cellar, it was pvc supply rattling against waste pvc, shoved old towel up between, problem solved!
  • Way to go Jamie & Fizz!
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • HomerJSmith
    HomerJSmith Member Posts: 2,309
    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
    Fizz Member Posts: 547
    Thanks Homer! Sounds logical