12-20-2002 I have the pesty sewer flies too. I have had them for 3-4 months. I have used bleach 4+ gallons, home defense and df5000 not all together, tried one for a couple of weeks then another. I have 2 bug zappers going in the basement 24/7 and sticky fly paper strips around the sewer. I think the flies are in the drainage tiles that lead into the sewer. How do I get them out of there? How do I get rid of these things for good? Please help!! Going Buggy