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

https://telegra.ph/Leak-Discovery-101-Fixing-Hidden-Pipes-Issues-in-Geelong-Houses-04-17

Sewage system odours inside can indicate a completely dry trap, cracked air vent, or partial blockage; Geelong residential properties with huge trees or older drain lines may require CCTV examinations to locate invasions and prevent recurring smells.