Drain Fly

Natural Habitat

Damp environments high in organic matter, such as bathroom drains, sewers, septic tanks, and compost piles.

Diet & Feeding

Larvae feed on the gelatinous film of bacteria, fungi, and organic sludge found in drains; adults feed on liquid carbohydrates and sewage.

Behavior Patterns

Poor fliers that often crawl on walls near drains. They are most active at night and have a life cycle of 7 to 28 days from egg to adult.

Risks & Benefits

They do not bite or transmit diseases to humans but are considered a nuisance pest. They can benefit ecosystems by helping to break down organic matter in sewage and compost.

Identified on: 3/10/2026