You found a 2-inch Schedule 40 PVC that sat outside for years in NYC.
It was a makeshift gutter runoff on a shaded wall.
It saw cold winters and wet weather.
Now you want to reuse it for plumbing vents.
Quick Q&A
Q: Can I reuse old outdoor PVC for my vent pipes?
A: Maybe, but only if it is DWV-rated, still sound, and your local inspector accepts it.
First, check the stamp on the pipe
The vent pipe is part of the drain, waste, and vent system.
In many areas, PVC DWV is listed in ASTM D2665.
Some Schedule 40 pipe is dual-rated for pressure and DWV.
If the pipe has no clear markings, skip it for vent work.
In NYC, plastic piping must also be third-party certified.
Helpful references:
How sunlight and weather affect PVC
UV light mostly changes the outer skin of PVC.
That change is usually very shallow.
But long exposure can reduce impact strength over time.
Your pipe had limited sun, which helps.
Field checks before you reuse it
- Look for chalking, deep fading, or a flaky surface.
- Check for cracks at the ends and old strap points.
- Make sure the pipe is round, not oval or warped.
- Cut off the first 6 to 12 inches from each end.
- Clean it well before primer and cement.
Also, do a small glue test.
Make one joint using the correct primer and cement.
Let it cure for the time on the cement label.
Then try to twist it apart by hand.
If it fails easily, scrap the old pipe.
Don’t forget the part above the roof
Even “inside” vent systems end up outdoors at the roof.
Any PVC exposed to sunlight should be protected.
Water-based latex paint is a common option.
Should you just buy a new pipe instead?
For most vent jobs, new 2-inch PVC is not expensive.
The new pipe also avoids inspection headaches.
Reuse can be fine for low-stakes projects.
But vents matter for odor control and safety.
A cracked vent can leak sewer gas into the walls.
My practical recommendation
If you need a permit or inspection, use new, clearly marked PVC DWV.
If this is uninspected work, reuse only the best pieces.
Keep reused pipe indoors and away from UV going forward.
I’m Chris Mayer, writing for Plumbing 101.