Stinky sewage gas in bathroom
We recently remodeled an older home including installing 2 new bathrooms, drains and vents. Each drain has a vent going into the attic, which join together to one pipe that vents out through the roof.
I have noticed in the past couple days the smell of sewage gas increasingly becoming more unpleasant from the main bath. We don't have a vanity installed in that bathroom as of yet (but have duct taped off the drain), nor do we have any fixtures (shower, toilet or sink) installed in the adjacent master bathroom - which by the way, doesn't smell in the least.
I asked my husband and he did install a wax ring in the (smelly) bathroom toilet. Why does it stink? Is it a vent or drain problem?
Also, don't know if this is related or not, but the smelly bathroom shower water has a strong gas smell when I first turn it on. Any answers on this? Are the two related?