Drain Flies
Drain flies, also called moth flies or sewer gnats, are small, fuzzy, moth-like flies that breed in the organic film that lines drains, sewer pipes, and septic systems. They are poor fliers and are typically found resting on walls and ceilings near their breeding sources. They are common in bathrooms, kitchens, basements, and commercial food service areas with chronically wet drains. Their fuzzy wings and erratic, moth-like flight pattern make them easy to identify. While individually harmless, large populations indicate drain maintenance issues.
Species in This Group (1)
Key Behaviors
Drain flies breed in the gelatinous biofilm of bacteria, fungi, and organic debris that coats the interior of drains, pipes, and sewage treatment filters. They are weak fliers that stay close to their breeding source. They rest with their wings held roof-like over their bodies, giving them a distinctive triangular silhouette. Adults live one to three weeks and are most active in the evening.
Risks & Concerns
Drain flies do not bite or transmit disease but are a nuisance indicator of organic buildup in plumbing. In large numbers, they contaminate food preparation surfaces in commercial kitchens. Their presence in healthcare facilities is unacceptable due to sanitation standards. Addressing drain fly infestations requires cleaning or treating the organic film in drains rather than spraying adults.
Need Help With Drain flies?
If you're seeing signs of drain flies in or around your home, professional treatment is the fastest way to stop the problem. Lotus Pest Control offers free inspections to identify the issue and recommend the right solution.