Basement Bathroom Smell

[Khoa Le]

I notice a sewer smell from the pipes above the basement bathroom door. I ripped the drywall ceiling and notice the pipes have this black gunk. Not just one area. Other places have this black gunk too around the pipes. The smell has reduce significantly. I'll monitor it daily to see if smells again. It's especially worse when it's hot outside.

 

[Geofd]

the bigger pipe looks like a vent (galvanized) the other is gas pipe watch the threads on the vent for possible leaks