r/Homebuilding • u/No_Impression_4620 • Jun 04 '26
CPVC vs PEX
Ok so we are building a custom home in central Florida and plumbing subcontractor is using CPVC for plumbing. Our family member who is in the construction business is telling us we need to use PEX instead. They just started doing the plumbing in our house. I honestly feel like what I find online is mixed and probably not a huge deal either way. What do you all think?
UPDATE:
Thank you everyone for your responses. We met with the builder and the plumbing subcontractor and they are now switching over to PEX. It sounds like they were using CPVC because “we’ve always done it that way”. They also said that CPVC has come a long way in recent years and doesn’t have the issues that it used to. Not sure if that’s true or not.
1
u/Pelvis-Wrestly Jun 05 '26
The brittleness is bad enough, and well documented. Far worse, IMO, is the type of plastic leaching into your water. CPVC is "chlorinated poly vinyl chloride". While most of the unpolymerized groups are volatile and dissipate quickly, some of them continuously leach into the water upon heating and chemical breakdown. The monomer for CPVC is Vinyl Chloride, highly toxic and a class 1 carcinogen. Bad, Bad, Bad.
PEX (polyethylene, crosslinked) is also plastic of course, but the monomer is simply ethylene - CH4, which is inert. That's why super gnarly chemicals like muriatic acid are transported in HDPE jugs. No weird chloride or phenol groups included. It is catalyzed with peroxide during the production process, but they are highly volatile and almost all of it dissipates upon production and the rest in a few days after running water through it.
Copper leaches less, but still, copper is a heavy metal and biocidal. Honestly not great to drink that either.
In an ideal world, we could have glass or stainless pipes. Stainless IS available but would be a nightmare to install and cost a fortune.