We just bought a 30 year old house with PVC drain lines. There is a loud ticking noise in the drain line when running water in the upstairs bathrooms. i think it is worse when running hot water but haven’t really been able to narrow it down that well. At first i thought it was a dripping noise but it is way too loud for dripping.
I think it might be expansion in the pipes but that seems odd since they have been i use for 30 years.
Any ideas what it is and what i can do to fix it?
Thanks,
mike in michigan