5 Reasons You Suddenly Have Gnats in Your House

It’s a universal truth: Gnats are the unwelcome house guests that show up uninvited—and then refuse to leave. While they’re harmless to humans, spotting one moseying around still gives us the ick, because it usually means something nearby is starting to rot. 

But those overly-ripe bananas on the counter aren’t the only thing drawing them in. “Anything sweet, moist, and slightly decayed is just the deadly combo,” says Nicole Carpenter, president at Black Pest Prevention. “But even one of these conditions is enough to attract gnats.” 

There are plenty of common household habits and scenarios that can unintentionally entice these pesky little flies. Here, experts break down what might be luring gnats into your space—and how to keep them from overstaying their welcome.

You’re Overwatering Your Plants

If you tend to generously water houseplants, you might want to rein it in. According to Scot Hodges, VP of professional development and technical services at Arrow Exterminators, one common mistake people make is overwatering their indoor plants. This creates a moist soil environment that fungus gnats are attracted to. 

To prevent this, ensure plants have good drainage, don’t let water sit too long in the planter saucer, and allow the soil surface to dry completely before watering again. (Bonus: This will almost certainly prevent root rot!)

You Ignore Leaky Plumbing Fixtures

Many of us don’t address minor plumbing issues, like a leaky faucet, until they become a serious problem, but these moist environments—which harbor mold and mildew—are ideal locations for an infestation.

“You’ll likely know it’s time to clean the shower drain when moth flies appear or come back,” says Trenton Frazer, lead entomologist at Aptive Pest Control. “Even damp dishcloths and condensation around garbage disposals can contribute to the problem.”

Gnats are attracted to moisture, organic material, and light, which is why they are frequently found around damp areas, decaying food, and illuminated surfaces, adds Frazer.

You Let Dirty Cups Sit Around too Long

Surprise—gnats are not just attracted to fruits! They consider almost anything laced with caloric content and moisture fair game for their breeding grounds, Hodges explains. So those dirty glasses or cups that haven’t been emptied (and even unrinsed cans and bottles in the recycling) are technically potential food sources for them. 

Essentially, keeping things as tidy as possible will go a long way in prevention. “For other species commonly referred to as ‘gnats,’ such as fruit flies and drain flies, the biggest mistake most homeowners make is not adequately sanitizing the home,” Hodges points out.

You’re Not Cleaning Your Garbage Disposal the Right Way

According to Carpenter, garbage disposals are full of everything gnats need to thrive and lay eggs, and the longer you keep them uncleaned, the more it can offer to gnats. 

“However, people also make the mistake of using something like a mix of baking soda and vinegar or just store-bought cleanser,” Carpenter adds. “These neutralize odors and break down some surface grime but don’t scrape off dirt accumulated on walls and hidden spots.”

She recommends first adding your baking soda and vinegar or enzyme-based cleaner, then tossing in ice cubes for physical scrubbing.

You Use a Single Garbage Can for All Types of Trash

It might be a pain to start dividing your trash, but if you’re dealing with a bad case of gnats or fruit flies, it could be worth investing in two types of bins. Carpenter notes that having just one trash bin for both organic and non-organic waste is a common mistake that easily attracts gnats.

“Food scraps, peels, or coffee grounds start to decay long before the bin is full enough for you to empty it,” she explains. “That creates the perfect conditions for gnats.”

Note that it’s imperative to keep garbage cans clean and tidy, especially during the summer. Take out trash frequently, or every day if you have a bad swarm, and regularly wash the bins.