Hello, I have had sewer flies for almost a year. At first the bathroom on bottom floor which is on slab had issues with bowl not sitting right on flange. This was fixed and at first seemed like it worked. Then a few months later (March) they started again. We had sewer company come in and saw low spot in sewer line and while we had to break slab and replace we also pulled up laundry sewer pipe that feeds in sewer pipe hat had about 4 foot crack. We feel confident that was our problem but, even though most of soil removed and cemented back with new PVC, we still see sewer flies My main question is how long will it take for the lies to go away. When work was being done there was hundreds al over laundry room and bathroom. They were there for hours and then pipes were closed. We kept vacuuming them but we still see them for 2 days now. Do you think these are residual or new ones? How long will soil take to dry out. We are going nuts! Please help.

Make sure you have water in all traps. Also, I suggest you pour bleach into each trap to kill fly eggs inside. Also, make sure you have traps on every plumbing fixtures. Caulk around the base of the toilet. Seal all cracks in the concrete. If you have clean-out in that room, make sure it is properly sealed. Same goes for sewer ejector lid ( if you have one )

See if that helps


Milo

The wet soil under the slab can be a breeding ground. With no idea of the climate in your area, how long it will take to dry is impossible to answer. Milo's suggestions about sealing around your plumbing are good preventive maintenance. You could also consider an enzyme drain cleaner or a long handled brush to remove the soap scum/organic build up in the drains instead of the bleach. That scum is often where eggs are laid.