Drain Fly

Natural Habitat

Typically found in moist locations with organic matter, such as drains, sewers, septic tanks, and damp compost.

Diet & Feeding

Larvae feed on the gelatinous film of bacteria, fungi, and decaying organic matter in drains; adults primarily consume nectar or liquid organic matter.

Behavior Patterns

Poor fliers that often crawl or take short, hopping flights. They are most active at night and are frequently seen resting on walls in bathrooms or kitchens.

Risks & Benefits

They do not bite or transmit diseases to humans. However, their presence indicates a buildup of organic slime in plumbing, and in large numbers, they can be a nuisance and potentially transport surface bacteria mechanically.

Identified on: 5/28/2026