Planning to finish my basement bathroom and also add a Kitchen sink just outside the bathroom wall to wash dishes when needed.

1. I understand why we need plumbing vents but I am unable to figure out a plan on how to vent my bathroom. Please check the attached layout. Closest bathroom that "might" have a vent is about 20' away.

2. Can AAV (Air Admittance Valves) be used here.

Thanks
Naveen

Hello Nastik,
If the basement was roughed-in already, there is a good chance vent was put in by the builder. It may be capped off in the ceiling.

Question: What's directly above this basement ?

You are not saying what Plumbing Code you fall under. I work under UPC. We have to vent every plumbing fixture. Vents can be combined into on 2" vent above flood line and either lead above the roof or to be connected with other vent on 1st floor. We are not allowed to use AAV's.

Hi Milo,

Thanks for the response.

I am in Charlotte, NC and upon checking (online), we follow IPC 2006.

My main problem is that I do not see any vent stack going up through the basement ceiling. I checked in the attic and found a vent stack coming out of my 2 second floor bathrooms. Is there a way I can connect to the existing vent stacks or any other (easier) solution.

I am pretty sure we can use AAV as I see one installed to my kitchen sink. But I want to avoid it if I can get a better solution.

Thanks again.
Naveen

Hi Naveen...

I can't speak to AAVS in your area... completely illegal in my area. If they are legal in your area you would need to install the AAV so it is "readily accessible" via an access panel of some kind or easily accessed under the counter/sink base... check with a local plumbing inspector just to see if the AAVS are legal.. OK?

Now, looking at your picture suggests that you only have the one drain pipe coming out of the floor for the sink drain/vent... right? No other pipes... right? If so, then you have a wet vented bathroom and technically speaking you CANNOT ADD A KITCHEN SINK to a wet vented bathroom... *OUCH*!

You cannot add a washing machine or a kitchen sink to a wet vented system... anywhere that I know of... so let me know what pipes are coming out of the ground.

A wet vented bathroom is where a 2" sink drain and vent get used as a toilet vent and the tub/shower vent...great system in that it utilizes only one vent instead of three vents like where Milo works. The idea here is that it is uncommon for all three fixtures to get used at the same time so some codes allow using the sink vent as long as it gets increased to 2".

If you install a washing machine or a kitchen sink on a wet vented system the sheer volume of water from these fixtures can actually siphon the PTRAPS of the fixtures and that can allow sewer gasses to enter into the house... a health hazard by any means!

Let us know more...


Mark

PS: Look up in the ceiling for a pipe marked FV (future vent). If present then this is where you connect the 2" vent for the basement bathroom. If not, you can connect the 2" vent from the basement to a vent upstairs at 42" off the finish floor.