I read your answers to the two posts above about flies or gnats in every room. I also have the same problem. I didn't think your answers fully addressed this problem. I have poured bleach in all my drains, even the floor drains. I have even temporarily sealed them up. There are no vegetables/fruits in my house. No houseplants. No drain leaks. They are so bad, I don't want to eat at home because they fly around and land in my food. They wake me up at night landing on my face. They are much more than bothersome, they are ruining my life. They kind of look like Phyroid (spell ?) Flies. Where else do they come from??