Sewer gas smell in bathrooms

[Catman]

Serious sewer gas smell in two bathrooms. Plumber has come back and installed new wax rings on toilets multiple times. We smoke tested system and smoke was present under one toilet. Plumber installed wax ring again and still smelled. He installed a new toilet also. Still had smell. We thenmpressure tested the whole system and it held five pounds for five minutes. Remounted all of the toilets and fixtures and still have sewer gas smell in two bathrooms. Any ideas would be greatly appreciated. Thanks.

 

[johnjh2o]

Just how did you pressure test the whole system? That would require capping all the waste lines at the fixtures, plus the main line.

 

[BobMaine]

Crack in flange under toilet? Sink in room have ineffective trap and gas getting past it? Vent pipe plugged?