Hello,
We are putting a half-bath in a small guest house, and I'm having a hard time figuring out if the toilet can be vented with a wet vent (through the sink drain/vent) if the sink is upstream of the toilet. Can anyone tell me? I'm pretty sure (I wouldn't mind some professional confirmation here) that we could wet vent it if the sink were downstream. Or that if we want the sink to be upstream of the toilet, that we could put a vent downstream of the toilet, and that if the sink is close enough (6 feet, since it's a 3"?), that the sink could then use the same vent as the toilet ( So, traveling upstream from the main drain, it would go vent, toilet, and then sink at the end.)

Do I have this at all right?
Thanks!
Carrie

Hello,
We are putting a half-bath in a small guest house, and I'm having a hard time figuring out if the toilet can be vented with a wet vent (through the sink drain/vent) if the sink is upstream of the toilet. Can anyone tell me? I'm pretty sure (I wouldn't mind some professional confirmation here) that we could wet vent it if the sink were downstream. Or that if we want the sink to be upstream of the toilet, that we could put a vent downstream of the toilet, and that if the sink is close enough (6 feet, since it's a 3"?), that the sink could then use the same vent as the toilet ( So, traveling upstream from the main drain, it would go vent, toilet, and then sink at the end.)

Do I have this at all right?
Thanks!
Carrie

Hi Carrie,

Yes you may wet vent the toilet through a downstream connection of a vented lavatory. Most bathroom groups are roughed in like this.
Toilet connects to sewer main. Lavatory connects to toilet drain and runs a vent off the top the stubout tee out the roof or revents back into a dry vent in the attic.. The toilet wet vents through the lavatory vent and the shower connects to the lavatory drain and is wet vented by it. This is a normal rough in and is acceptable both by local and state codes and also The Standard Plumbing Code Book. Good luck, Tom