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Radon vent

user-1137156 | Posted in Building Code Questions on

Can a Radon vent be tied, legally, into a plumbing vent or must it remain separate through the roof?

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  1. Expert Member
    Dana Dorsett | | #1

    Short answer: No

    Slightly longer answer: Pressurizing or depressurizing a plumbing vent with a fan can defeat the P-traps on the drain plumbing. The drain traps are only keeping out the gases by the liquid in the trap. Fans powerful enough to depressurize a basement slab can often drive 2-4 water-inches, sometimes more, and interfere with the operation of the drain traps.

  2. GBA Editor
    Martin Holladay | | #2

    Dana is right. You can't use a plumbing vent stack for a radon mitigation system. For more information, see this article: All About Radon.

  3. user-1137156 | | #3

    Martin & Dana,
    When I asked the question I was thinking only of a passive system which I'll be installing as a precaution. If it turns out that a fan must be added it certainly must be separate but if passive is sufficient fewer holes in the roof is desirable. In the article "All About Radon" Martin specify s PVC pipe for the Radon vent. Is there any reason that ABS pipe should not be used for this purpose?

  4. GBA Editor
    Martin Holladay | | #4

    Whether the system is active or passive, you still need to keep the riser for the radon mitigation system separate from your drain-waste-vent (DWV) plumbing system.

    You can use either PVC or ABS for your radon riser. Even copper would work, but copper is expensive.

  5. user-1137156 | | #5

    Thank you!

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