First, avoid panic but take it seriously. A mild occasional smell from a seldom-used bathroom might just mean the trap has dried out, but a strong or constant sewage odour deserves attention. A safe basic step is to run water into all drains – floor traps, seldom-used sinks, guest toilets. The water refills the U-shaped traps that normally block smells from coming back up.
Next, check if any drain covers are missing, cracked or poorly sealed. Make sure toilets are firmly fixed and sealed at the base; a broken wax ring or seal can let odours escape. If the smell persists after these simple checks, it’s time to call a plumber rather than mask it with air fresheners.
Persistent sewage smell can indicate blocked vents, partial line blockages or leaks in hidden pipes. In addition to being unpleasant, it can be unhealthy. So basic water traps first, quick visual checks second, and then a professional if the issue doesn’t disappear.