We are building a house with a septic system. The basement toilet will drain to a sump and be pumped out to the septic system. What size does the vent need to be from this toilet to the vent header in the attic?

Hey ynysddu:

That vent will traditionally be run full size 2" to the attic.

If there is also a lavatory in this basement bathroom... you can "WET VENT" the toilet by connecting the lavatory into the 2" toilet vent before going upstairs to attic.

Now...what are you doing with the vent from the ejector pit? That should also be run full size 2" into the attic, and in some areas is supposed to penetrate the roof separate from the other vents in the house... or, you may be able to connect into the other vents in attic just prior to penetrating the roof... BUT THAT CODE IS STATE SPECIFIC... so would need to call a local plumbing inspector and ask him what he wants you to do with sump vent.

Let us know if you need more... glad to help... Mark

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