HouseSymptoms field intelligence
Likely causes
Failure modes and building-physics mechanisms connected to the clues that support or weaken them.
cause 60ventilation-and-airflow 8roof-envelope 7building-structure 6drain-waste-vent 5appliance-connections 4domestic-water-supply 4exterior-wall-envelope 4cooling-and-air-conditioning 3foundation-and-ground 3insulation-and-air-barrier 3site-drainage 3space-heating 3electrical-distribution 2leak 2windows-and-doors 2
cause⌁
Sewer backup
Wastewater reverses through a drain due to blockage, surcharge or system failure.
cause⌁
Failed toilet seal
The hidden connection at the toilet outlet allows wastewater or odor to escape.
cause⌁
Drain vent obstruction
Restricted venting changes pressure and drainage behavior.
cause⌁
Dry drain trap
Trap water evaporates or is siphoned away, removing the sewer-gas barrier.
cause⌁
Partial drain blockage
Accumulated material slows flow and changes sound or odor patterns.
