Here’s one I haven’t seen before. The bathroom vent pipe is terminated in the waste vent pipe. This was a townhouse complex so I assume all were done this way. An interesting way to add waste fumes to your bathroom.
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A+ for creativity.
No, you got it, James…That is Not Good!
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I would rather see the bathroom exhaust to the attic than that configuration.
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If you’ll excuse the pun, they did a real crappy job.
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Yes, and that is the 1st time I have seen that. Thanks for sharing it.
Moisture must be dripping out of the bath fan, Yep. 
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YUCK! Ugh!
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Morning, Richard.
Hope this post finds you well.
Upon reading the threads title seeing I had some time to kill between reports, I thought to myself, 
hm…there is nothing wrong with a bathroom Vent terminating in Waste pipe??? That’s were they terminate.
After reading the OP’s post, I saw the error you made. The Thread should have read; “Bathroom Exhaust Duct Terminating in Soil Stack.”
Poor hypotheses. Plumbing vents are required to be atmospheric not mechanical.
Thanks for sharing.
Regards.
Robert
PS: Inspection 2 days ago. Look familiar?
There is a method to this madness, let me explain. it’s one less protrusion through the roof surface which equates to one less potential leak point. No?
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I always tried to put it out the gable under the insulation. 
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No, plumbing vents require atmospheric pressure. Added pressure, from a mechanical bathroom duct, will affect trap primers.
The most common trap primers are connected to a water line and activated ‘via pressure fluctuation’ from a nearby urinal or water-closet flush that maintains the water levels. Added pressure can empty seals or added circulation induce seals to lose their water seal by evaporation.
Maintaining the liquid seal, water in this case, will prevent the ‘backflow of sewer gas’ into the buildings or rooms where the traps are installed. That trickles down to DWV trap seals under sinks, bathtubs, shower stalls and laundry tubs as well.
Hope that helps.
Robert, I was being facetious.
That’s the reason for the 
in my post.
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Ops. Guess I was being literal.
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