Drain Fly / Moth Fly / Filter Fly

Natural Habitat

Commonly found in bathrooms, kitchens, and basements, particularly around drains, sewers, septic tanks, and other areas with standing water or decaying organic matter. They can also be found outdoors in areas with high organic debris.

Diet & Feeding

Larvae feed on decaying organic matter, sewage, fungi, and microscopic organisms found in drains, sewers, and other damp environments.

Behavior Patterns

They are quite common indoors. Adults are attracted to light and often found near windows. Adults do not feed and their sole purpose is reproduction. Larvae feed on various organic materials, preferring damp conditions. They undergo complete metamorphosis.

Risks & Benefits

Potential Risks: Can be a nuisance pest, especially in large numbers. While generally not considered a health risk, they can potentially carry bacteria from foul breeding sites to food surfaces. They can also indicate a plumbing issue or excessive organic build-up. Benefits: In natural environments, their larvae contribute to the decomposition of organic matter.

Identified on: 8/11/2025