I own a high effiency washing machine from sears. When we do laundry the room that the washer/dryer is in gets a septic oder in it. I pump the septic tank yearly (not town service) and have even had the septic guy look around in the tank as he's doing it. I have no other septic related problems in the house that I know of and never have a septic smell outside. What could be causing this? (oh, the septic guy sees nothing wrong.) I'm thinking maybe the machine is not fully draining through the pipes and some is being left or something?? Anyone ever heard of this? The house is 30 years old and it's the original system. My septic guy told me at the last pump-out (last July) that the yard would show signs if it was failing and it is not. He said the grass would REALLY be growing awesome over the leaching field again, it looks like the rest of the yard. Help, at my wits end with this.

Try using the washer empty, and in the powder drawer and conditioner drawer, pour some Zoflora in. Let me know what happens after you do that please?

A blocked vent pipe could be causing the trap in the washer drain (or other fixture) to be syphoned dry. When you smell the odor, pour about a pint of water down the washer drain and any other fixture. Pour slowly. If odor goes away you have a blocked vent pipe.

Do you have P-Trap installed on the washer drain ?

It can also be that you don't have vent and as the water exits Trap, it allows some sewer gas to enter stand pipe and than the room.

Do you have P-Trap installed on the washer drain ?

It can also be that you don't have vent and as the water exits Trap, it allows some sewer gas to enter stand pipe and than the room.

I know squat about plumbing but I do not think I have a P-Trap. I believe it's gas exiting the drain pipe that drains the washer. I'm going to ask a local plumber for their opinion.

Try using the washer empty, and in the powder drawer and conditioner drawer, pour some Zoflora in. Let me know what happens after you do that please?

I've never heard of this I'll check it out. And thanks everyone you've given good advice.