When a sewer smell enters your house it's very unpleasant and unwanted.  The smell can happen for a variety reasons including: crack/opening in pipe, clog, dry trap, previous back up, broken seal, gap in wax ring.

There are different ways to attack each problem in order to find and eliminate the smell.  The most common way of finding any cracks in the pipe is to smoke test the drain lines in the area of the smell.  The smoke will show if any gas is being allowed to escape the pipe.

Madden Sewer recommends having a technician inspect the home and area where the smell is strongest.  After his inspection, he will recommend the best step in fixing the problem.