I have a fitting in a wall which began leaking with mold developing on the wall board. When I took out the wall the culprit was a fitting between a female threaded copper fitting and a male PVC fitting in a hot water line. I initially took out the PVC fitting and fitted the joint with a new fitting placing a teflon pipe dope in the joint. Next morning water was dripping from the joint apparently working its way up through the threads. I then tried redoing the joint with wrapping the male PVC threads with a teflon tape. Same result. THe joint leaked the next morning. I then cut out the female copper fitting and sweated in a new copper female fitting and wrapped the female end of the PVC with teflon tape. It still leaks. Is the problem that the piping is PVC and NOT CPVC. Would I get a better fit with the CPVC. If it is then I will need to tear out two walls to replace the PVC piping as CPVC fittings do not fit on the PVC pipe.

Thanks for your help!

Try a copper threaded male adapter and a PVC female adapter, use two turns of teflon tape and see if that doesn't hold water. BTW, What kind of pressure are we talking about? Regards, Tom

Thanks Speedball. Changing the fitting to a male worked. I assume this is because the copper expands when the hot water flows through the joint so now the joint tightens inside the PVC when used rather than loosens itself from the PVC.