The smell is not sewer gas it is more like the smell of a car carpet
that has been wet .
This is a tub shower with a 2 handle faucet . The drain has one of those
toe tap plugs ( no lever ) .
Started smelling this about 2 weeks ago and found it is coming from the
tub drain . The drain has water in the trap and the smell continues even
after using the tub .
Plugging the drain by pushing the toe tap down stops the smell .
I hear no strange sounds or find the trap empty . The other tub in the
house is about 8 feet away in the other bathroom with the same type
drain setup and it does not smell .
I pulled up carpet & find no wet or signs of it . smelling the
floor/carpet gives no smell ( just sneezing ) The smell comes directly
from that tub drain .
The house is 5 years old and no hard use as im the only one who ever
lived here .