Drain fly

Drain flies, sink flies, moth flies, or sewer gnats (Psychodidae) are small true flies (Diptera) with short, hairy bodies and wings giving them a "furry" moth-like appearance, hence one of their common names, moth flies. There are more than 4,700 known species worldwide, most of them native to the humid tropics. Moth flies sometimes inhabit human drains and sewage systems where they are a harmless but persistent annoyance.