House is 2 yrs old and on septic tank. Drain line has a trap and all appears normal. 85% of the time there's a odor that comes from drain opening. have snaked line and it's clear. Any ideas, we're getting tired of that nasty odor. Thanks, Paul
P traps only work when they have water in them. Check for leaks at the P trap if you can. pour a couple of gallons down the shower drain 2-3 times a day see if this helps. if it works you might have a slow leak.
I have had a few clients with this same problem with showers they hardly use.
People forget the water in a p-trap will evaporate.