PVC pipe?

OK, Why is it a bad thing to have PVC pipe for water supply in a home?

I need clarification.

I understand that you can’t use PVC for hot water, you have to use CPVC.

But why can’t you use PVC for cold water?

The main water line to my house is ¾" PVC and thats acceptable.

What am I missing?

PVC does not have the pressure rating that CPVC has. PVC is better suited for drain and waste pipes.

PVC can be used for supply, but it runs the risk of deterioration sooner. Why would one want to take the risk of water damage, when CPVC is as available and not much more expensive?

OK, so the risk is the pipe may burst.

But its OK to use outside because if it breaks it wont damage anything.

I didn’t know CPVC was stronger than PVC.

My house has copper branch supply & PVC main. 20 years never a problem. Except for that little mishap with the shovel… but, we wont go there.

I only know what they tell me…

I’m not a plumber–don’t have the crack for it–but I’ve installed a lot of such things in my insipid little life.

I’ve read somewhere PVC is OK for cold water lines. It is generally not allowed for distribution plumbing because it is hard to tell which lines are supposed to be hot and cold just by looking at them, so you do not know if they are plumbed corrrectly.

I don’t know how much truth there is to this, but it makes sense to me.:slight_smile:

Schedule 80 pvc will work but may not be legal in your area depending on the plumbing code. When I worked under the UPC it was not legal to use in a distribution system.

Depending on where you live pvc can cause problems in cold weather. PVC expands and contracts a lot so any large temperature differentials may not be good.

It appears to me to be allowed by per IRC Table P2904.5. (ASTM D 2464; ASTM D 2466; ASTM D 2467; CSA B137.2) (Schedule 80, Schedule 40) I don’t see where there is any distinction between hot and cold water supply piping and the allowed use of PVC. Would like hear more on this.


Long story short.
CPVC is acceptable for hot and cold.
PVC is acceptable for cold in some applications and per AHJ.

Locality dominates decisions in such.

Midwest… you’ll see a bunch of it. Entire houses plumbed hot and cold with schedule 40. They don’t even sell Pex, CPVC in a lot of places.

Ask your AHJ or local building authority.