Ni987 t1_ixltgh9 wrote on November 24, 2022 at 12:23 PM

Have you checked if any of the siphons in the drains are being sucked dry? Under-pressure in the drain pipes (due to blocked vents or bad design) can suck the water out of the siphons essentially allowing the air from the sewer to vent directly into the room? Would typically occur when other apartments down stream flush water through the system.

GiraffeAnatomy t1_ixpbg1i wrote on November 25, 2022 at 6:00 AM

I second this. Try filling all drains and pipes with water. Grab pitchers, fill them up, and empty them down the drains, you may need to do this every few weeks as the water evaporates out of the pipes.

If for some reason you only have straight pipes down to a source you can't get to, try installing P traps if you can so water keeps the air from the sewers from coming up your pipes/drains and into your bathroom.