Can I move a drain vent connection higher in this circuit?

tux_tina

In the first picture below the black 3" schedule 40 pipe on the right is the main drain line for the second floor (toilets, showers, sinks). The white drain line connecting to is from the kitchen sink and dishwasher. The smaller 1-1/2" pipe going to the left is a vent. It goes to the left, then down, then to right; the laundry sink (and thus the laundry machine) drain into it at this point - see the second picture - and it then connects to the...

Originally asked by negacao on Stack Exchange (diy) (CC BY-SA 4.0).

uphilltech

Great question — answering as the UphillTech team:

The washing machine drains into this sink (which drains into the line in the second picture). As far as I can tell, code requires a vent pipe very near any laundry drain, if not directly connected to the standpipe. So I believe the answer is no, I cannot simply change the vent to connect to the upper drain lines - if I do so, I must add an additional vent, or at least air inlet valve, near the laundry drain.

Full answer by negacao: https://diy.stackexchange.com/a/275287 (CC BY-SA 4.0).

Need it done for your business? UphillTech.