Commercial Pest Services - Here it is, this drain was really clogged.

Here, I immediately saw that the drain grate was "packed to the gills" with garbage and assorted debris. Decaying organic matter, especially the slimy build-up of film that coats the sides of drains, is a major attractant for certain pests to feed and breed. With these infestations, we commonly find drain flies, various small flies or "gnats," including moth flies, phorid flies, and fruit flies.