Drain Fly

Natural Habitat

Damp environments rich in organic matter such as drains, sewers, septic tanks, and wet compost.

Diet & Feeding

Larvae feed on the gelatinous film of bacteria and organic debris (biofilm) in drains; adults primarily consume nectar or liquid organic matter.

Behavior Patterns

Poor fliers that often crawl on surfaces; they are most active at night and are frequently found resting on bathroom or kitchen walls.

Risks & Benefits

They do not bite or transmit diseases to humans, but their presence can indicate a plumbing issue or hygiene problem; they help decompose organic waste in pipes.

Identified on: 1/13/2026