I have been RVing for going on 20 years. Also, I have been involved with residential contracting for quite some time as well. Many years ago, ABS replaced copper as the preferred material for plumbing the drain systems in residences. Then maybe 20 years or so ago, PVC replaced ABS as the preferred material for DWV systems, and is in use everywhere today, EXCEPT in RV's. The RV manufacturers seem to have stuck with ABS for some reason. Does anyone have knowledge as to the reason they continue to use ABS rather than PVC? Is it less susceptible the vibration rigors of the open road? Is it less prone to rupture from freezing? Is it less brittle when cold? There must be a bona fide reason they don't use PVC, which is much more readily available.I'm about to replace a ruptured section of ABS with PVC, unless there is a compelling reason not to. Thoughts?

PCV does not handle vibration as well, but I suspect most of it is simply cost.

http://drainwastevent.com/PVC appears to be superior to ABS and is an accepted replacement.I think the glue might be a bit different so watch the transition.

May have to do with UV exposure for outside use with the tanks. Could also be that sealers used at tank connections work better with ABS.White PVC is not good when exposed to sunlight. Grey PVC (more expensive) is for exterior use.That is something to consider in the overall cost of keeping 2 different construction materials stocked for separate indoor and outdoor use.

ABS is more impact resistant and probably has more wall strength but I'm not sure about the latter.

ABS vs PVC DWV plumbing | Good Sam Community

OldSoldier53
Explorer
Jun 09, 2014
I am renovating an 14 ft 1968 Chateau TT. Probably had copper in it but that was poorly replaced with PVC. I have removed all the PVC and will be replacing it with PEX. After looking at all the posts and doing a little research of my own, it looks like that is the best bet. It should be easier to install and will last longer.

BTW. It anybody out there has any info on old Chateau trailer, please share. I am most interested to know what make and model the original furnace and fridge were.

Thanks
Lantley
Nomad
Jun 09, 2014
The OP started the thread referring to DWV piping. Drain Waste Vent.
Somehow the the replies are referring to fresh or supply water piping!

Gets confusing when you start mixing the drain and supply piping.
Wouldn't want to shower with black water even if it is piped in pex!
OldSoldier53
Explorer
Jun 09, 2014
After doing a little research, I am going with PEX for my TT restoration. Took out PVC some of which was broken. All of which was a bad job. Don't know what was there before. It is a 1968. At about $30 for 100 ft and probably the same amount for fittings, seems like a no brainer.
dougrainer
Nomad
Jun 10, 2014
OldSoldier53 wrote:
After doing a little research, I am going with PEX for my TT restoration. Took out PVC some of which was broken. All of which was a bad job. Don't know what was there before. It is a 1968. At about $30 for 100 ft and probably the same amount for fittings, seems like a no brainer.

PVC and Copper was common until about 1978-80 for fresh water piping. The problem with PVC (not to be confused with PEX) is, when it froze, it shattered and splintered in long lengths. After 1980, some used Copper and some used Plastic(pex type) for fresh water piping. By 1990, almost all used Plastic tubing. Doug
Harvey51
Explorer
Jun 11, 2014
We had an ABS elbow crack on a sink drain running several feet down then 7 feet across the RV to the grey water tank. I think it was just too long and too rigid. I replaced with a rubber elbow and have not had any more trouble.

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