Drain Fly Larva

Natural Habitat

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

Diet & Feeding

Decaying organic matter, algae, fungi, and bacteria found in bio-film/slime.

Behavior Patterns

Larvae live within the gelatinous film of drains; they are sub-aquatic and can survive in low-oxygen environments. They pupate near the surface of the slime before emerging as winged adults.

Risks & Benefits

They are generally harmless to humans but indicate a buildup of organic material in plumbing. While they do not bite, they can be a nuisance in large numbers and may mechanically transport bacteria from drains to food surfaces.

Identified on: 6/1/2026