I sometimes get a strong sewer gas smell in my kitchen sink, dishwasher (next to kitchen sink) and washer (7 feet from sink). Had plumber out to clean sewer lines and he said that I have a broken sewer line and need to get a plumber with a camera. I don't think he is correct because I only smell sewer gas some of the time. Sometimes it is so bad can hardly stand it and then other times no smell and I'm talking days or more at a time. Could it be that my vent is possibly stopped up? I would think if I had a broken sewer line that it would smell sewer gas all the time. Any ideas?