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Pest Education • DFW Pest Control
Drain Fly Control in DFW
Fuzzy little drain flies breed in the gunk inside slow or unused drains. Learn how to find and clean the source to clear them out.
Family-OwnedVeteran-OwnedSince 2016
Reviewed and updated June 2026
At a Glance
Drain flies breed in the organic film inside drains and traps. Cleaning that film, not spraying the air, is what eliminates them.
Quick Facts
- Look: Tiny, fuzzy, moth-like
- Breeds: Organic film in drains, traps, and pipes
- Sign: Flies resting on walls near sinks and tubs
- Concern: Nuisance; indicates a drain biofilm source
What Are Drain Flies?
Drain flies, also called moth flies, are tiny fuzzy, moth-like insects that rest on walls and surfaces near sinks, tubs, and floor drains. They are weak fliers that move in short hops.
They breed in the gelatinous organic film that builds up inside drains, traps, overflow holes, and seldom-used pipes, where larvae feed unseen.
How to Eliminate Drain Flies
Pouring bleach down a drain rarely works because it does not remove the film the larvae live in. The fix is physically cleaning the breeding film.
- Identify the source drain by covering drains overnight and checking for flies.
- Scrub the inside of the drain and remove the biofilm with a brush.
- Use an enzyme drain cleaner to break down organic buildup.
- Run water in unused drains so traps do not dry out and harbor flies.
Treat the Source
Match the approach to the pest and conditions, not just the ones you see.
Explore services →Prevent Return
Reduce moisture, food, and entry points so the problem does not come back.
Request an estimate →Treatments are selected and applied per their labels. Tell us about children, pets, edible gardens, beehives, and other sensitive areas before service, and follow all preparation and re-entry instructions. More on pet- and pollinator-conscious treatment →
Common Questions
Where are drain flies coming from?
From the organic film inside a drain, trap, or seldom-used pipe. That film is the breeding site, so the flies will persist until it is physically cleaned out.
Will bleach get rid of drain flies?
Usually not on its own. Bleach passes through without removing the film the larvae live in. Scrubbing the drain and using an enzyme cleaner works better.
How do I find which drain is the source?
Cover each drain overnight with tape and check the next day; the drain with flies trapped on the underside is the breeding source.
Sources & Further Reading
Guidance changes over time. Follow current product labels and local recommendations. This page is educational and is not medical advice.
Need Help With Drain Fly?
Call or email for a free estimate. We’ll recommend an approach that fits your property.