utility sink drain

[buckeye_diy]

I am a Ohio DIYer. I have a utility sink in the garage and need some professional advice on how to correctly install the drain. Need advice on where to tie the drain into the existing system and how to properly vent it. I have attached a sketch of locations and rough measurements. By far, the easiest existing drain to access is the kitchen sink drain. I guess the first question would be if it is acceptable to tie into the kitchen sink drain. Thank you all in advance for your help.

 

[Reach4]

I think you would not be allowed to run the combined drainages thru a 1-1/2 inch pipe. Kitchen sink is 2 DFUs and I think utility sink is two more DFUs for a total of 4. 1-1/2 inch pipe is OK for 2 DFU, and it looks like 2 inch pipe is only good for 3 DFU. So combined you would need at least 2-1/2 inch pipe, which almost does not exist. See section 709 of https://codes.iccsafe.org/content/IPC2018/chapter-7-sanitary-drainage

So how about running another drain pipe, and join at the 3-inch. Or replace the proposed shared pipe with 3-inch.

Easiest venting under IPC will be an AAV near the utility sink. Where would be handiest for that for you?

Drain lines need to slope downhill. After the vent they can be steeper. Before the vent, the slope is usually 1/4 inch per foot.

 

[Sponsor]

 

[buckeye_diy]

Thank you for your response. You have me re-thinking the entire project which is good. I will work on it and get back to see if my new ideas would be acceptable.

As for the venting. There is hardly any room at all under the sink. Is it OK to terminate the vent in the attic with an AAV?

 

[Reach4]

As for the venting. There is hardly any room at all under the sink. Is it OK to terminate the vent in the attic with an AAV?

If it was accessible to replace, I would think so. That would be unusual.

This is a garage. I infer it is beneath an attic. Same attic shared with the house? What were you envisioning the first 5 ft of drain line out of the sink looking like? Drain pipe hidden under drywall, or will it be exposed? An AAV can be as little as 4 inches above the trap arm ( drain pipe before the vent).

 

[buckeye_diy]

The drain will go through drywall in the garage and the directly down into basement. I guess I am slightly concerned about the aav being below the water level of the sink even though I know it is designed for that. (I know I tend to worry about everything) Looking closer, there would be room to mount it below the sink.

 

[Reach4]

The drain will go through drywall in the garage and the directly down into basement. I guess I am slightly concerned about the aav being below the water level of the sink even though I know it is designed for that. (I know I tend to worry about everything) Looking closer, there would be room to mount it below the sink.

Yes. Another common way would be to run a pipe higher, and put the AAV behind a grill and recessed box designed for the purpose. https://www.homedepot.com/p/STUDOR-4-1-8-in-x-7-1-8-in-Mini-Recess-Box-with-Grille-20380/202531637 is one example.

There is also the Rectorseal Magic Trap.

 

[buckeye_diy]

Now that is VERY interesting. I had no idea something like that was available. You have given me so much to consider. Again, thank you for your help! I'm sure I will have some more questions over the next couple days as I try to plan out the best way to do this.