Drain odours inside can show a completely dry catch, cracked air vent

https://felixrbys875.image-perth.org/geelong-home-plumbing-headaches-from-obstructed-drainpipes-to-hidden-leaks-when-to-call-a-regional-plumbing

Drain odours inside can indicate a dry catch, split air vent, or partial obstruction; Geelong residential or commercial properties with big trees or older sewage system lines might require CCTV evaluations to locate invasions and avoid persisting scents.