This just started....when my Wife does laundry, we get a Septic Odor in the Laundry room. We bought the house last year, and this is the first time we have had this issue. The waste line for the Laundry has a trap, so it puzzles me how gasses can enter past the trap???....the odor only occurs when doing laundry....when she's done, we just air out the room and the odor disapates. The Septic was pumped just before we closed on the house almost 1 year to the day....it just doesn't make sense to me.....any ideas???