Hi,

I'm completing my basement and adding a small kitchen. My intention is to run the drain to a waste stack several feet away and use a cheater vent under the sink. The waste stack is 3" and has a toilet from the main floor connecting to the top of the stack. About 1 foot below that is a 1-1/2" tee that connects that bathroom's tub and sink. There is also a cleanout tee near the ground on the stack and a 1-1/2" vent with a cleanout a few feet from the main stack.

I'd like to connect my sink in just above the 3" stack's cleanout, but I've heard that might not be to code since it's below a toilet. However, that bathroom's tub and the sink are, so I'm not sure.

If it's not to code, could I connect it to the 1-1/2" vent poking out of the cement instead?

Thanks,

-Don. :confused:

Both ways would work. Connecting to the 3" waste stack is acceptable as long as a AAV,(Air Admittance Valve) is installed between the trap and the stack. Also, you may connect to the 1 1/2" vent only if it's a dry vent. If you're staying in code you must not be over 3 1/2' from the trap to the vent. Good luck, Tom

Thanks speedball. So, I will use an AAV right under the sink, after the trap, and from what I can tell the vent pipe just goes from the cement floor up through a void space in the upstairs wall and to a roof vent. So, by dry, I'm assuming you mean, no water, so that's what this would be. It's right in line with the 3" stack, so I'm guessing it's for that.

If this is the case, I can connect to it for my sink drain? (still using the AAV under the sink)That would be nice since it's a few feet closer.

Thanks for the help. I really appreciate it.

-Don.

I would use the AAV in both ways as added insurance just in case it isn't a dry vent. Good luck, Tom