Symptoms
- Small flies hovering near the sink or disposal
- Flies seem to appear from the drain area
- Problem worsens after leaving fruit or produce scraps in the disposal
- Flies return a day or two after wiping the counter
Likely causes
- CommonFood residue inside the disposal and splash guardRotting organic matter in the grind chamber is an ideal breeding site.
- CommonResidue in the drain line or trap below the disposalFlies can breed in gunk further down than a quick disposal cleaning reaches.
- PossibleFruit or produce left near the sink drawing flies in generallyFlies attracted to counter fruit can also explore the drain.
What to do
- Turn off and unplug the disposal, then lift the splash guard flaps and scrub underneath thoroughly.
- Run ice cubes through the disposal with cold water to knock loose residue from the chamber walls.
- Pour baking soda followed by vinegar down the drain, let it sit 10–15 minutes, then flush with hot water.
- Cover the drain opening with tape overnight; if flies appear stuck to the underside, that confirms the drain as the breeding source.
- Remove ripe or overripe fruit from the counter near the sink while addressing the problem.
- Repeat the cleaning every couple of days for about a week to break the breeding cycle.
Tools and parts
- Old toothbrush
- Ice cubes
- Baking soda
- Vinegar
- Tape (for the test)
When to call a pro
If flies persist for more than a week or two despite thorough cleaning, a plumber can check the trap and drain line for deeper buildup.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.