Identify the type: drain flies, fruit flies, or fungus gnats
For drain flies: clean and scrub sink/bath drains, overflow drains, and nearby traps
Pour boiling water down drains regularly (safe for your plumbing)
Use an enzyme drain cleaner daily for several days
Remove and clean drain screens, P-traps, and any gunk buildup
For fruit flies: remove ripe/overripe fruit and clean produce thoroughly
Empty trash and recycling more frequently
Seal food in airtight containers
Clean sticky residue from counters, under appliances, and inside bins
Make vinegar traps (vinegar + a few drops of dish soap) and place near sources
For fungus gnats: let the top 1–2 inches of soil dry out between waterings
Water from the bottom (so the soil surface stays drier)
Remove standing water in saucers and discard excess
Replace or top-dress with fresh sterile potting mix if infestation persists
Apply a biological control such as Bacillus thuringiensis israelensis (BTI) to soil per label
Use yellow sticky traps near plants to reduce adults
Remove dead leaves and organic debris from pot surfaces
Consider repotting if larvae persist
For all types: vacuum adults and webbing areas near windows and doors
Seal cracks and keep screens intact
Reduce indoor moisture and improve ventilation
Run dehumidifier if humidity is high
Wash garbage areas and mop floors where spills occur