How to Get Rid of Drain Flies

I keep seeing drain flies even after cleaning down sinks and surfaces. How can I get rid of drain flies?

Drain flies look like tiny, fuzzy moths and often rest on walls near sinks or floor drains. However, other small flies may appear in the same areas, so it helps to identify which flies are causing problems.

To get rid of drain flies, find and remove any wet organic buildup where their larvae develop. Wiping sinks and surfaces does not reach the slimy film inside drainpipes, so new adults can keep emerging despite regular cleaning. Hidden leaks or damaged wastewater pipes may also be supporting an undiscovered fly breeding site.

Start by following these steps:

• Find the source: Check sink drains, floor drains, mop sinks, and sink overflow channels. 
• Remove buildup: Have trained staff scrub accessible drain walls, strainers, and the undersides of drain covers with a suitable brush. Arrange professional drain cleaning where deposits are out of reach, or your staff is untrained to do so.
• Support routine cleaning: An appropriate foaming or enzyme-based drain cleaner may help remove organic deposits. Follow product directions and never mix cleaning chemicals.
• Check hidden moisture: Inspect refrigeration drip trays, condensate pans, leaking pipes, and persistently wet areas beneath equipment.
• Monitor progress: Keep drains on a documented cleaning schedule and record sightings. Trapping adult flies alone will not eliminate the breeding source.

Do not rely on bleach or fly sprays as the main solution, as this rarely addresses the whole issue. Never pour insecticides into drains. If in doubt when using DIY solutions, always consult a fly control professional.

If flies persist after thorough drain cleaning, arrange professional pest identification and a plumbing inspection. A pest professional can use emergence monitoring to identify which drains are producing flies. We support a variety of commercial sites with professional bioremediation services.