House Re-Pipe Using CPVC (Hot) and PVC SCH 40 (Cold)

**ckelley** · 08-11-2010, 10:11 PM

I just recently undertook a DIY house repipe replacing 40 year old galvanized pipe that developed a leak under the slab. I used cpvc for hot water supply and PVC SCH 40 for cold water. I installed the necessary water hammers and a heat trap at the water heater. The water heater is set at 95 degrees.

I was originally going to use cpvc through out but thought I could save some money by running PVC SCH 40 for the cold water supply since it is rated for residential water supply..not irrigation.

I am thinking of pulling the PVC SCH 40 out and replacing with CPVC. Should I replace this or keep it as is? I have not found any definitive explanations or pros/cons for or against. I live in Florida and ran the supply lines through the attic so the water temperature for the cold water supply gets hot until it is flushed out. Should this be a concern with PVC rated for water supply?

**Terry** · 08-12-2010, 01:06 AM

PVC is meant to be used underground, not above ground. Heat is a big factor in it not being allowed by plumbing codes for the cold water supply inside a home.

If you look at a plumbing code book, the table lists PVC for use as an underround building supply.
CPVC is rated for inside the home.

hj · 08-12-2010, 05:46 AM

PVC has a tendency to get brittle as it ages. You could have a system that lasts 40 years, or one that lasts 2 weeks, and there is no way to tell which it is until something fails. HOW MUCH did you save by going cheap?

**Wally Hays** · 08-12-2010, 05:48 AM

How much did you save by using PVC, about 8 bucks?

**ckelley** · 08-12-2010, 10:38 AM

I would have saved about 150.00. 10 FT SCH 40. Lesson learned. I figure I can replace all lines in about 4 hours or less. I have a pretty straight forward run with kitchen / wash dryer on one trunk and bathrooms on another..the baths literally share a common wall and are back to back.

The experience has been priceless..however next time I would turn it over to a pro for I do not have enough experience to develop the intuition with the "technicals" that can only come from experience.

**Terry** · 08-12-2010, 11:23 AM

Don't beat yourself up too much.
It's not obvious to a layman that PVC wouldn't be correct.

There are plenty of things I've done the hard way, against the best advice too.
I kept buying different video editing programs, and finally went with Premiere Pro. I just couldn't make the entry level stuff work for me.
If I added up all the beginner packages together, I could have bought the good one right off the bat.

**ckelley** · 08-12-2010, 11:29 AM

Well at least were talking about something I do know. I like Apple's Final Cut Express.

hj · 08-13-2010, 09:34 AM

CPVC would have cost $150.00 MORE? How big was the cold water system, and if it is that big, how can you redo it in 4 hours. I think I could buy enough PVC to do the entire hot and cold water systems for $150.00, (but then I would have to redo everything). You do realize, I hope, that since your body's temperature is 98 degrees, 95 degree water is "cool" so you have to use ALL hot water without mixing any cold, which will deplete the tank in short order, but at that temperature you might not notice that you are showering in cold water.