Drain Vent Clogged =link= -

You grab the plunger. You buy a $30 bottle of sulfuric acid sludge. You curse the plumbing gods.

Your plumbing isn't broken. It’s just holding its breath. Give it air, and watch the water fly. drain vent clogged

If you smell rotten eggs in the winter but not the summer, check your roof. Snow can cover the vent, or ice can narrow the opening to a pinhole. The DIY Diagnostic (Don't Go on the Roof Yet) Before you ladder up to the sky, do the "Bucket Test." You grab the plunger

That vacuum is the enemy.

When you flush a toilet and the shower drain burps air at you, that is air being sucked through the shower’s P-trap. The vent is supposed to supply that air, but it can't. So the system cannibalizes air from the nearest sink or tub, sucking the water seal dry. That seal is the only thing stopping sewer gas from entering your lungs. Lose the seal, lose the war. Your plumbing isn't broken