Drain odours inside can indicate a dry trap, cracked vent

https://share.relay.edu/eportfolios/217/tom-cruise/tips-on-keeping-your-plumbing-system-properly-maintained

Sewage system odours inside can indicate a dry catch, broken vent, or partial obstruction; Geelong residential or commercial properties with big trees or older sewer lines might require CCTV evaluations to situate breaches and prevent reoccuring smells.