Hi long time lurker first time poster here I noticed a smell coming from the shower drain recently tried the usual things I read online like bi carb soda vinegar hot water down there it didn’t go away then called a plumber he plunged it and put the snake down the drain and he said he couldn’t find anything clogging it, anyway after about 5 mins in the shower it starts to smell of sewage gas again.It does not smell when I am not using it.
Any drain plumber out there knows what I could do the house is on a slab (13 yrs old)I called the plumber back he now seems to think the rubber seal has gone on the toilet and that is where the smell is coming from am reluctant to get him back again
Get a 2-3 plumbers to look at it and see what they all say.