I have a new home: about 3100 sq/ft, two story, slab on grade. It's now about 4 months old, but since the first week of moving in, when running the dishwasher or washer (laundry), the house fills with the smell of sewage. Both the washer and dishwasher are brand new units. I had the plumber come out, because I believed something was not properly flushed, etc. He told me the it was because the traps were dry and that I need to run water in all the traps everyday. I've been running all the trapped sinks, etc. in the house for a few minutes a day and it doesn't go away. I had the plumber back out and he said the same thing, that the traps are dry. I explained that I run the sinks, tubs, showers in the house everyday, and he basically said I am lying. I haven't had a second opinion yet, because I feel like this should be covered under the plumbing warranty. Does anyone have any ideas of what the problem could be? Maybe, the plumbing isn't properly vented somewhere? Perhaps something wasn't cleared properly? I'd love some ideas to go back to these guys to make sure they do or find the problem. I mean, it's pretty embarrassing to have people come over and only to be overwhelmed by the smell of sh....