Plumbing question - sink relocation to wall with 3” main drain and others

[schmalzy]

Alright gents,

Wife has me remodeling kitchen. Old sink was in the island, now moving to interior wall. Most plumbing lines on this wall already. My question is which line should I tie the sink drain into and then do I need to run a separate vent?

I’m a Fire sprinkler guy but have almost zero plumbing knowledge. I’m assuming the 3” line (middle) is the main drain/sanitary line. Originally I thought the 1.5” line (far right) was a drain line as well due to the clean out present but then started thinking it was sized to be a vent line?

2” (far left) really not sure but assume may be drain line for washing machine upstairs or another part of vent stack.


Current plan is to cut in a tee to 3” line and just drain sink into that. Do I need to tie it into a vent line? Just add an AAV?

Any help appreciated!

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[GSPHUNTER]

Yes tie into main 3" drain line, and yes to separate vent.

 

[bridgerbenson]

The 3” likely goes up and through the roof as the main vent stack, so if you tie your sink drain into it, it would be vented and not need another vent ran, correct?


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[GSPHUNTER]

Actually if you can verify one of those lines are a vent then you can tie into it.

 

[schmalzy]

The 3” likely goes up and through the roof as the main vent stack, so if you tie your sink drain into it, it would be vented and not need another vent ran, correct?


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Finding conflicting information on this. A “wet” vent is how I understand it.


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[TaperPin]

That must be the luckiest relocation ever! Water supply lines and waste all within arms reach - one in a million.

 

[schmalzy]

That must be the luckiest relocation ever! Water supply lines and waste all within arms reach - one in a million.

Right?? Definitely thankful on that end. I just don’t want to half ass it at this point since I do have everything there.


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[GSPHUNTER]

Finding conflicting information on this. A “wet” vent is how I understand it.


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Some areas allow wet vents. Surprising enough my area in southern ca. allows it.

 

[schmalzy]

Some areas allow wet vents. Surprising enough my area in southern ca. allows it.

Wondering if I just use the 3” line and throw an AAV on it and call it good


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[TaperPin]

In our area wet vents are ok and things always seem to work - can’t imagine physics being all that different in other places. Maybe with old mostly clogged plumbing there are issues, but modern waste lines are fairly trouble free.

The best change to our sink plumbing has been draining the dishwasher in a way that doesn’t go through the garbage disposal. That way, when I forget to run the disposal and dump coffee grounds in it, the dang thing doesn’t fill with waste water from the dish washer.

 

[schmalzy]

3” for the win. Called a local plumber who was super cool and talked through it all for free.

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[Bubblehide]

3” for the win. Called a local plumber who was super cool and talked through it all for free.

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I'd send him a nice gift with a thank you card.