Moth Fly (also known as Drain Fly or Sewer Gnat)

Natural Habitat

Typically found indoors in moist places like bathroom drains, sink traps, and sewage systems; outdoors near decaying organic matter or wet soil.

Diet & Feeding

Larvae feed on decaying organic matter, algae, fungi, bacteria, and sludge found in drains; adults essentially do not feed or may drink water/nectar.

Behavior Patterns

They are weak fliers often seen resting motionless on walls near sinks or tubs. They are most active in the evening and attracted to light. Their wings are covered in fine hairs giving them a 'furry' moth-like appearance.

Risks & Benefits

Risks: Generally harmless to humans as they do not bite or transmit major diseases, but they can be a nuisance and may mechanically transport bacteria from drains to surfaces. Benefits: Larvae help break down slime and sludge in drains.

Identified on: 3/6/2026