Gnat infestation - Ask Extension
I have found dead gnats by the hundreds all over my bathroom for the last week. Every day I thoroughly clean with bleach and apple cider vinegar spray...
Knowledgebase
Gnat infestation #407132
Asked June 14, 2017, 4:20 PM EDT
I have found dead gnats by the hundreds all over my bathroom for the last week. Every day I thoroughly clean with bleach and apple cider vinegar spray. I wipe everyone up and I kill any that may be living. They are usually dead except for 10 or so but it's literally over a hundred dead when I come and clean sometimes twice a day. I've tried boiling water down the drain after bleach, I've tried scrubbing the tub with baking soda and a brush. I've tried a bug bomb and it hasn't stopped yet. Any recommendations. We do have a window but it leads out to the back of the building with no plants remotely close.. only concrete. I tried cleaning the window seals with bleach as well. I've cleaned and come back in a less than an hour later there are multiple flying around or dead. I close the drains every time as well.
Cook County Illinois
Expert Response
Thanks for sending your message to us at eXtension.
You have already tried many of the things I normally recommend to get rid of gnats/fruit flies/drain flies. We may want to repeat some of them.
I have found that pouring a LARGE pot of boiling water down the drain will usually solve the problem of fruit flies that are breeding in the slime in the drains. At least, for a while. Do this with both the sink and the tub. You might also consider using some drain cleaner in these drains, to remove any of the slime coating the insides of the pipes. I think the products that produce a foam might be more useful.
Next: check the piping for the sink and toilet (and the tub, too) where it comes in from the wall. The gnats may be breeding on the moisture that is sweated off the pipes, and then following the outside of the pipes up into your bathroom. There are various coverings that are used on pipes to prevent condensation, and that will also insulate the pipes. At the minimum, get a can of expanding aerosol foam (for example, Great Stuff), and use that around any openings in the walls. This will form a physical barrier that the gnats can't get through.
Keep the bathroom window closed, in case the insects are coming in from outside. If you must have the window open for ventilation, see about getting a finer-meshed screen, which will help keep insects from flying in. Be sure that the screens and window fit tightly, with no gaps or holes.
It would be a good idea to try these techniques in the kitchen and in other rooms with plumbing as well.
Good luck!
You have already tried many of the things I normally recommend to get rid of gnats/fruit flies/drain flies. We may want to repeat some of them.
I have found that pouring a LARGE pot of boiling water down the drain will usually solve the problem of fruit flies that are breeding in the slime in the drains. At least, for a while. Do this with both the sink and the tub. You might also consider using some drain cleaner in these drains, to remove any of the slime coating the insides of the pipes. I think the products that produce a foam might be more useful.
Next: check the piping for the sink and toilet (and the tub, too) where it comes in from the wall. The gnats may be breeding on the moisture that is sweated off the pipes, and then following the outside of the pipes up into your bathroom. There are various coverings that are used on pipes to prevent condensation, and that will also insulate the pipes. At the minimum, get a can of expanding aerosol foam (for example, Great Stuff), and use that around any openings in the walls. This will form a physical barrier that the gnats can't get through.
Keep the bathroom window closed, in case the insects are coming in from outside. If you must have the window open for ventilation, see about getting a finer-meshed screen, which will help keep insects from flying in. Be sure that the screens and window fit tightly, with no gaps or holes.
It would be a good idea to try these techniques in the kitchen and in other rooms with plumbing as well.
Good luck!
Larry, Thanks. I will definitely try to pop out the sides of the tub to see if its something going on there. We just had a new whirlpool tub installed so that could be the case and there are panels on the side of the tub that I didn't consider. I just don't understand why they are already dead in the tub. But I will check and try the big pot of boiling water again.
Thanks
Thanks
