Whole-home control
Fungus gnats in your house
Written by Mustafa Ayan Fact-checked against university extension/IPM sources Last reviewed: October 14, 2026
Direct answer
To get rid of fungus gnats in your house, find every moist, organic breeding source, not just the plant you noticed them near: check all pots, saucers, cachepots, and drains. Let soil dry, put sticky traps in affected rooms, and treat infested pots with Bti. Treating one pot while another stays wet is the usual reason they return.
Why they end up in your house
Gnats get in on new plants, bagged potting mix, or through open windows, then settle wherever it's damp. Indoor air stays warm and stable, so a handful of gnats can turn into a population within a month or two.
Find every breeding source
- All houseplants in the room, including ones that look healthy. Check the top of the mix for damp, fungus, or algae.
- Saucers, trays, and decorative cachepots holding standing water.
- Large, rarely used plants whose soil stays wet for weeks.
- Seedling trays and cuttings in water or damp mix.
- Drains, garbage disposals, and trash cans (if they look more fuzzy and moth-like, you may have drain flies instead).
- Overripe fruit, if the flies hang around the kitchen. That's more likely fruit flies.
Clear the house room by room
Start in the room where you see the most adults. Dry out the surface of every pot, empty saucers, set a sticky card in or beside each plant, and treat the infested pots with Bti. Move to the next room once that one is under control. Isolate any new plant for a week or two with a sticky card before it joins the rest.
Sticky cards on windowsills and near lights help you see how widespread the problem is. Count them weekly. A falling count is the best sign you're winning.
Keep them out
Bottom-water, use fresh sterile potting mix, top-dress with sand or grit, and don't let water sit in saucers. A small number of cards left out for monitoring will warn you early if gnats return.
Common questions
How do I get rid of fungus gnats in my house?
Find all breeding sources, let soil dry between waterings, trap adults with sticky cards in each room, and treat infested pots with Bti. Expect several weeks for complete control.
Where do fungus gnats come from in a house with no plants?
Without plants, look for damp organic sources: drains with buildup, wet trash, overwatered soil in a potted tree or planter, or leaking areas with mold. Flies near drains are often drain flies, not fungus gnats.
Can fungus gnats live in my carpet or walls?
They need damp organic material to breed, so they don't breed in dry carpet. Adults may rest on walls and windows, but the source is nearly always moist soil or another damp organic spot.