In the bathroom below the drain has taken lots of water throughout ceiling, it has soaked all insulation and caused dripping from ceiling. My first impression was that it came from the vent.\n\nWe climbed the roof to find that the drainpipe is also near and the metal casing around was full of mud preventing flow and probably causing pooling of water. My suspicion is that during heavy periods of rain it caused a 3-4 inch barrier at drain and water entered the nearby vent, but talking with contractors they suspect that the drain pipe isn't properly sealed as this is common problem. \n\nI looked at neighbor houses and none seem to contain the metal filter (only a very open plastic filter).\n\nI cleaned the mud and tried to create more of a pooling area for drain pipe, but question still remains what could of caused the leaks. Any way of testing? Can we remove the metal filter (neighbors only seem to have plastic light bulb style one shown which allows for better water flow, etc.)? \n\nThe plumber is suggesting we cut open the wall to access drain pipe behind wood structure and they will come repair, but I still have my suspicions that it is just a flow issue.