A: I believe it is probably filter/moth/drain flies. This fly belongs to the family of flies generally called moth flies, because their scale-covered wings resemble those of a moth. They are very tiny – about 1/16 to 1/18 inch in length and light gray to tan. Their life cycle is seven to 20 days. Adult flies have the body and wings covered with dense, long hairs. Moth/filter flies breed in decomposing organic material, such as moist plant litter, garbage, sewage, and around kitchen or bathroom sinks and water traps in plumbing fixtures. You might consider removing the drain and clean out the source of food for the flies. Best chemical control methods aim at managing the maggots or larvae.
Q: I saw these small flies coming from the drain in my garage. What are they?