Where to source 4inch schedule 20 pvc pipe?

[Valleyslim]

Looking to pipe my dust collection system with 4 inch pvc pipe. Specifically schedule 20 because of its cost efficiency. I know rockler sells schedule 40 pvc pipe attachments but schedule 40 is 75$ per 10 ft as a opposed to 35$ per 10ft for schedule 20. I've called everywhere locally here in Idaho. pipe companies, building supply, sewer supply, electric supply, big box stores, hardware stores, plumbing repair, farm/tractor supply stores and no one carries it. Well 1 ace hardware had 2 sticks and i asked them if they could order more and they said its back ordered no eta. I might pick up those 2 sticks but i need about 40 ft worth. I called every online dealer that came up in search and they only sell 2.5 inch pipe. Anyone else have any other suggestions before i bite the bullet and just pay for schedule 40? i checked for sewer/drain pipe as in some states call it that instead of schedule 20 but when i asked, they told me it was schedule 35

[Coop]

I used white, 4” pvc sewer pipe and fittings from Home Depot.

[drzaius]

DBII electrical conduit is a thin wall PVC and is very inexpensive.

[Tom King]

Look in Lowes or Home Depot where the drainage pipe is.  It comes in white and greenish, but it might not be marked as schedule 20, or any schedule.