Schedule 40 PVC DWV & supply

Whole house schedule 40 PVC. I know it’s not acceptable for supply piping and pretty sure it’s not acceptable for DWV. ABS OK, PVC bad. Right?

I see no problem with schedule 40 PVC. That is most of what I see and have installed myself.


This is from the 2006 IPC

**608.8 Identification of potable and nonpotable water.
**In all
buildings where two or more water distribution systems, one
potable water and the other nonpotable water, are installed,
each system shall be identified either by color marking or metal
tags in accordance with Sections 608.8.1 through 608.8.3.

**608.8.1 Information.
**Pipe identification shall include the
contents of the piping system and an arrow indicating the
direction of flow. Hazardous piping systems shall also contain
information addressing the nature of the hazard. Pipe
identification shall be repeated at maximum intervals of 25
feet (7620 mm) and at each point where the piping passes
through a wall, floor or roof. Lettering shall be readily
observable within the room or space where the piping is

**608.8.2 Color.
**The color of the pipe identification shall be
discernable and consistent throughout the building.

**608.8.3 Size.
**The size of the background color field and lettering
shall comply with Table 608.8.3.

PVC Sched 40 is fine for DWV systems, just don’t mix them with ABS, PVC Sched 40 is not allowed for water distribution except for cold water distribution outside the building, if allowed by local codes…

Dale, there was only one water distribution system, if the definition of the term “distribution” is the same as the term “supply”. I don’t think “distribution” could be applied to DWV piping.

Kenton you are correct, I think Dale just missed it.


My personal opinion based on repairing ABS over the last decade.

PVC & ABS bad for water distribution. We could not use it where I lived. Under some circumstances PVC schedule 80 was acceptable.

I just got off the phone with the local bldg. dept. who said that PVC is not allowed for supply, but is allowed for DVW if the pipe is markeed “DVW”. This could vary from area to area. Probably best to check with local AHJ.

Hi Kenton,

I had an inspection in a different county where I normally do business and PVC was used for both the potable and waste.

The pipes were clearly labeled clarifying the difference with a magic marker. I didn’t regard the hot water piping as being allowed, but it was accepted by the AHJ after I call them also.

Schedule 40 is good up to 140 degrees I believe, I wouldn’t want it in my house but some authority’s allow it here. Some of the county inspections out in tim-buck-too you never know who allowed what when without calling to beg their indifference.

Dale, from what I’ve been able to gather, the problem with PVC is that it becomes increasingly brittle with age and so will break more easily as time goes on. Impact, water hammer and point stress from fasteners are apparently all a concern. -Kent

Dale I understand Non-Potable Water Systems to be different than Waste/Sewage systems. Is this not correct?

I believe it’s a preasure thing. Schedule 40 is not made for that high of preasure. DWV has no preasure.

The 1/2" was labeled 600 PSI, the 1 1/2" used for DVW was labeled 330 PSI.

Question??? If you are not using PVC SCH40 what are you using for drain & vent lines? I still see some PVC SCH30 in some older homes.

Don’t forget about CPVC!!! That is used for supply.

A note about PVC pipe below:

These are from manufactures not from a plumbing code book, but they do quote codes.

Jason, around here it’s mostly ABS with occasional cast iron for anything 4" or bigger. Older homes will have copper. -Kent

ABS I see in mobile homes & manufactured homes.

When I said older I wasn’t talking 1970’s… older than that I see 3-4" cast and copper is rare. I have seen lead under an old track home I used to own for the waste line…

Note: A lot of track homes have lead supply coming from the street to the water meter.

Yes…non-culinary use…:smiley: …for either type!

Nice try Dale.

An example of non potable water would be landscaping piping or pool piping downstream of the vacuum breaker.

Waste piping has solids in it.

When you ask silly questions I try to respond with a silly answer…:stuck_out_tongue: