The drain flies are short and have hairy bodies and wings that give them the appearance of a moth. A Drain Fly can grow up to 2mm long. This species of flies have tan colored body and appears to be grey. Wings of the flies get densely covered with hair. The drain flies inhabit in plumbing drains or sewage systems. The females lay eggs near the sewage bed and the eggs hatch within 1-6 days. The larvae feed on the sludge-like organic matter and it takes around 10-15 days to mature. The pupae take 1-3 days to reach adult stage. Though these flies are harmless, they can annoy when swarm over the head or any area.