How to Get Rid of Drain Flies & Gnats Fast

Learn how to banish pesky drain flies quickly and without any harsh chemicals! It might be easier than you think.

Gnats or drain flies are persistent house guests, whether they’re in the kitchen sink, a tub drain, the basement, or anywhere else for that matter. In the blink of an eye, one or two stray drain flies can multiply quickly making clearing the air difficult! Drain flies aren’t dangerous, nor do they pose any serious health risks, but they are certainly annoying and may spread bacteria.

You can get rid of these nagging insects in a few simple steps, with several methods to choose from depending on the severity of the issue and what household cleaning supplies you have available.

As there are hundreds of different types of gnats and flies, we’ll start by taking a quick look at what constitutes a drain fly so you know you’re taking the right approach.

Identifying Drain Flies

A drain fly, known scientifically as Psychodidae, is a type of small fly known for its furry, moth-like appearance. Drain flies are smaller than house flies and look a bit different, too; measuring 1/8th of an inch in length, drain flies are short-bodied, grayish-brown colored, and have fine hairs on their wings. Their wings, when not in flight, loosely resemble the shape of a heart.

Drain flies are sometimes referred to as sink flies, sewer flies, sewer gnats, drain gnats, or moth flies. Per their name, they hang around near drains, in pipes, and wherever there’s stagnant water. They don’t fly particularly well and will live for a few weeks before dying.

While you’ve likely encountered a number of different types of gnats in your kitchen or near a drain, drain flies aren’t to be confused with fruit flies, fungus gnats, gall gnats, or any other of the 600+ types of gnats that exist.

Here’s an up-close picture of a drain fly to help you with identification:

Cute, right?

What Causes Drain Gnats in the First Place?

Drain gnats gravitate to stagnant water and places that are damp, soggy, or filthy, such as in a drain, near the sewer, in humid pipes, or amidst the decaying leaves in a gutter. They feed on types of organic matter and bacteria often found in thin films on the surface of water. Certain times of the year, such as rainy springs or humid summers, can also influence the prevalence of drain flies.

Seeing that a little water often pools around or right inside of shower drains, sink drains, and on the bottom of the tub, it’s common to see gnats in the bathroom, kitchen, or basement. They’re found indoors and outdoors, though unless they’re in a large quantity near your house there’s no need to remove them outside.

Are Drain Flies Always in Drains?

Not necessarily! Have drain flies indoors but no drains nearby? There may be something else damp or even mildewy attracting them. Check for signs of where the drain gnats seem to be coming from. And try cleaning in all of those household nooks and crannies, such as the back corners of counters, along baseboards, window sills, around air vents, on the top of your refrigerator, and anywhere else that seems appropriate.

Are Drain Flies Harmful?

No! Drain flies don’t bite or sting, and won’t transmit diseases to humans. However, seeing that the areas they inhabit tend to be rather dirty, they can spread bacteria to surfaces or onto any exposed food items out in the open.

Methods for Getting Rid of Drain Flies

There are a number of ways to remove drain gnats. While we’re going to look at how to get rid of drain flies specifically, some of these methods will also help eliminate fruit flies, fungus gnats, and other types of related small-winged insects.

Essentially, you’ll want to kill the drain flies at the source by cleaning your drains (the right way) as well as setting traps to catch those still flying around. From there, keep an eye out to see if your treatment was effective! If drain flies persist in large numbers despite repeated DIY attempts, it may be time to call an exterminator or plumber.

These natural ways to get rid of drain flies are often just as (if not more) effective than chemicals. As tempting as it may be to pour bleach down your drain, it can cause damage to your pipes, a septic system, and may even create a tox gas if it mixes with other cleaning fluids already present in your drain, such as vinegar.

Below is a list of natural ways to remove drain flies quickly and effectively so that they won’t come back! Note that while putting out traps gets rid of drain flies, they won’t target the source directly.

It’s important to clean out any drains or areas where you think the drain flies may be coming from. This helps remove the drain fly larvae and eggs, in addition to cleaning excess scum, grime, and gunk from the pipes and around the drain’s surface.

Boiling Water

This is a great, simple method to start with and can be done in tandem with other methods listed below. It won’t be the most powerful, but does provide a good starting point and may be all you need to do.

Easy does it, just pour a few cups of boiling water down your drain once or twice a day for one to two weeks, or until the flies go away. The boiling water kills drain flies, larvae, and their eggs, and can also help clear away small excess buildups of scum and bacteria. Make sure to take necessary precautions to avoid burns and do not look directly over the drain as you pour.

Apple Cider Vinegar Drain Fly Trap

A classic. Fill a cup or small bowl with around six ounces of apple cider vinegar. Add in a few drops of liquid dish soap (around two teaspoons should do the trick) to the ACV and then mix together. You can also stir in a few teaspoons of sugar to sweeten the deal for your curious house guests.

Cover in plastic wrap, securing the wrap in place with a rubber band so it’s sealed along the edges. Poke a few holes in the top with a toothpick or the tip of a knife (be careful!) — the holes should be just big enough so the drain flies can enter. This apple cider vinegar trap also works great for capturing other types of gnats and fruit flies.

White Vinegar, Salt, and Baking Soda

Ready to clean your drain? Mix together ½ cup of salt, ½ cup of baking soda, and 1 cup of white vinegar. Pour slowly into the drain and let it sit overnight. Rinse in the morning with a few cups of boiling water.

Before doing this process, you can use an old pipe brush or sponge to scrub out the drain. This helps remove surface scum and residue that drain flies love.

House Plants

A number of herbs and small house plants keep drain flies away. They hate the smell and will think twice before setting up shop!

Some of these plants include basil, mint, lavender, and marigold. You can plant them in pots inside near windows or anywhere where they’ll receive adequate sunlight. Keeping these plants throughout the year also helps prevent drain gnats from returning long-term.

Essential Oils

Despite how we may love the smell of essential oils, many of which are beneficial for our health and wellbeing, drain gnats hate them! Spray a little essential oil about the house to brighten your room and keep drain flies away. They especially dislike lavender, eucalyptus, lemongrass, and peppermint.

Tape on the Drain

This is a quick trap you can set that also can help you detect the source of your pesky drain flies. Simply seal your drain with duct tape or a similar type of tape — the drain flies will get stuck on the tape trying to fly out. You can leave the tape for several days in a row if needed, but never tape active drains needed to drain areas and keep them from flooding!!

Other Methods

For more severe cases of drain flies, (or maybe they’re just not leaving despite your efforts), it may be wise to contact an exterminator or plumber. You can also try store-bought drain fly removal chemicals or drain cleaners, if you must, such as Drano — which clears pipes of debris and also will kill drain flies.

Ways to Prevent Drain Flies From Returning

Once you’ve eliminated drain flies at the source and from your space, there are a few things to do to keep them from returning. Be sure to keep drains and areas where moisture may collect clean, wiped down, and disinfected.

You can clean drains with soap and a brush, and flush them with boiling water, as mentioned above, every few weeks or when they seem dirty. If you have drains that don’t get a lot of use, run water through them every few days to make sure no standing water collects and begins to attract drain flies!

Choose Eco-Friendly Cleaners

Now that you know how to get rid of drain flies (in a way that’s good for the planet) make sure you have the right household goods and products when you need them. Shop zero waste essentials at Public Goods and look for our natural, sustainably created cleaners and other household items.

While harsh chemicals may be needed in more severe cases of drain fly inhabitations, in most cases things like vinegar, essential oils, and even houseplants will be all you’ll need. With Public Goods, an eco-friendly lifestyle is good for the planet, good for your home, and good for your wallet.