Sewer odours inside can indicate a completely dry trap, cracked vent

https://telegra.ph/Geelong-Homeowners-Overview-Stopping-Blocked-Drains-and-Other-Pipes-Headaches-04-18

Sewage system odours inside can suggest a completely dry catch, fractured air vent, or partial obstruction; Geelong homes with huge trees or older sewage system lines may require CCTV assessments to find intrusions and prevent reoccuring scents.