You might expect to deal with mildew in your bathroom, but you probably aren't prepared for the sight of gnats there. They gather in your sink near the drain, on damp walls in your shower and even inside your toilet bowl. The gnats are drawn to the water they find in your bathroom.
Gnats in your bathroom aren't crawling up through the drain or flying out of the trash can. The most common gnats found in homes are fungus gnats. With dark bodies and clear wings, they look like tiny mosquitoes. They come from the soil of infected houseplants. Fungus gnats don't bite, so they cannot hurt you or spread disease to your family. The flying adults don't feed, so they aren't a danger to your plants or the food in your kitchen.
While fungus gnats aren't dangerous, they are a nuisance. The adults are attracted to light sources and water, so they gather around lights, window and sinks. The bathroom is the most common room to find them in, followed by the kitchen. The adult gnats lay eggs in houseplant soil. Their larvae live in the dirt, feeding on fungal matter. The larvae can also eat a plant's roots, causing it to wilt. Extreme infestations can badly damage plants.
Get rid of the gnats in your bathroom with insecticidal spray designed to kill flying insects. You'll find it at home-improvement and garden stores. Killing the gnats in your bathroom is only a temporary solution. A new generation of larvae in your infested houseplants will mature and show up in your sink and shower. To get rid of the problem, you need to kill the larvae. Use a soil drench available at garden-supply stores. It soaks into the dirt in a pot, killing larvae without damaging your plant.
To check if all gnats are dead, hang sticky strips around your plants. If you see gnats stuck to them, then the infestation isn't over. For a badly infected plant, sometimes it is easiest to either move it out doors or throw it away. Keep gnats out of your home by carefully inspecting new plants before bringing them indoors. Avoid reusing old potting soil that has been outdoors for new indoor plants. Allow the dirt in your houseplant pots to dry between waterings because fungus gnats prefer wet soil.