We are having a similar problem with our laundry room. For the past week there is a sickly septic smell in the laundry room which is across the hall from our 3 month old baby’s room. It is so upsetting. And we can’t seem to get a plumber out to figure what is going on. I’m also worried about the effect of the smell on our baby and ourselves. We had a similar problem with one of our bathrooms last year and the plumbers had to reset the toilet. That worked but now it seems that the problem as moved to another room. What does it mean to put a trap in? How costly?