Sewer Fly or Drain Fly

Scientific Name: Psychodidae (e.g., Psychoda altenata, Clogmia albipunctata)

Order & Family: Diptera (True Flies), Psychodidae (Moth Flies or Drain Flies)

Size: Typically small, adults ranging from 1.5 to 5 mm in length.

Sewer Fly or Drain Fly

Natural Habitat

Commonly found in moist environments with decaying organic matter, such as drains, sewers, septic tanks, compost heaps, and areas with standing water. They are often found indoors near sinks, showers, and toilets.

Diet & Feeding

Larvae feed on decaying organic matter, fungi, algae, and microorganisms found in moist environments like drains, sewage, and compost. Adult flies do not feed or feed on nectar/water.

Behavior Patterns

Larvae develop in areas with high moisture and fed on organic matter. Adults are attracted to light and often found flying or resting on surfaces near food sources or decomposition. They are generally weak flyers.

Risks & Benefits

Potential Risks: Can be a nuisance pest, especially when present in large numbers indoors. While generally not considered a public health risk for disease transmission, they can carry bacteria from contaminated areas to surfaces. Heavy infestations can indicate underlying plumbing issues. Potential Benefits: In outdoor environments, their larvae play a role in decomposition of organic matter.

Identified on: 7/2/2025