Non metallic pipes "ticking"

[Marc M]

Any of you guys hear plastic pipes make a ticking sound , only when the hot is tested? I have it in my own house, and heard it yesterday at a house I inspected. Thought is might be expansion/contraction of the pipes or movment? Oh, its continuious, not when you turn fixture on/off.

[H.G. Watson, Sr.]

Pretty common with PVC DWV not supported properly or allowing for expansion/contraction.

[Jerry Peck]

Thought is might be expansion/contraction of the pipes or movment? Oh, its continuious, not when you turn fixture on/off.

Probably expansion and contraction due to heat and the clamps on the pipes are too tight, not allowing for proper movement of the piping, this causes the piping to scrape back and forth through the clamps instead of slide easily through the clamps.