Drain Fly

Natural Habitat

Humid areas with decomposing organic matter, notably drains, sewers, septic tanks, and damp bathrooms.

Diet & Feeding

Larvae feed on the gelatinous film and organic slime found in drains; adults primarily consume liquid carbohydrates like nectar or simply live off stored nutrients.

Behavior Patterns

Poor fliers that often crawl on walls or fly in short, jerky movements. They are most active at night and are frequently seen resting on bathroom walls near plumbing.

Risks & Benefits

They do not bite or sting and are generally harmless to humans, though they can be a nuisance in large numbers. In the ecosystem, they are beneficial as decomposers that help break down organic sludge.

Identified on: 5/14/2026