How do I get rid of drain flies?
Foam treatment of the drain throat weekly for three weeks breaks the breeding cycle. Surface spray and bleach don't reach the larvae inside the biofilm.
Why it happens
Drain flies, also known as phorid or sewer flies, breed and feed in the organic sludge that builds up inside drains. This gelatinous biofilm provides a protected environment for larvae, shielding them from conventional cleaning liquids poured down the drain. The adult flies seen in the facility are a symptom of this hidden breeding ground within the pipes.
What to check
To begin, mechanically scrub the drain opening and pipe throat with a stiff brush to break up the top layer of the biofilm. Follow this with a professional enzymatic foam treatment, which expands to coat the entire pipe interior and digest the organic matter where larvae develop. Avoid using hot water or caustic chemicals, as they are ineffective against an established biofilm and can damage plumbing. Check and clean all floor drains, kitchen lines, and utility sinks, especially those that see infrequent use.
When to call a professional
If a widespread infestation persists after repeated treatments, or if flies appear in numerous areas, it can signal a more significant problem in the drainage system. Issues like a cracked drain line under the slab, a poorly maintained ejector pit, or a dry P-trap can create alternative breeding sites. A strong, persistent sewer gas odor accompanying the flies is an urgent warning sign that requires an immediate investigation of the entire wastewater system.
How Luften handles it
Luften addresses drain fly infestations at their source. We use a professional, bio-based foaming chemistry that clings to pipe walls, dissolving the biofilm breeding ground without harming pipes. Our specialists can identify contributing factors, such as issues in an ejector pit or grease trap, during a complimentary site survey. We consolidate drain and fly control with other facility maintenance needs into a single, managed service program to prevent recurring problems.
Drain Odor Elimination and Drain Fly Program