Drain Fly

Natural Habitat

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

Diet & Feeding

Larvae feed on the gelatinous organic film (biofilm) that builds up in drains and pipes; adults typically feed on nectar or contaminated water.

Behavior Patterns

They are weak fliers and often seen crawling on walls near sinks or tubs. They are nocturnal and complete their life cycle from egg to adult in about 1 to 3 weeks.

Risks & Benefits

They do not bite and are generally harmless to humans, but can be a nuisance 'pest' and may theoretically transport bacteria from drains to food surfaces. They benefit ecosystems by breaking down organic waste in drainage systems.

Identified on: 4/5/2026