how to get rid of drain gnats

How to Get Rid of Drain Gnats: 5 Ways

Also referred to as drain flies, drain gnats are a real nuisance, especially when they infest your home. While these tiny flies aren’t harmful to you, having them and their eggs in your house is certainly annoying and embarrassing, especially because they might be viewed as a sign of poor hygiene.

That’s why many homeowners who have these drain flies in their homes are eager to learn how to get rid of drain gnats for good. This article offers you five effective ways to get rid of these drain flies.

How to Get Rid of Drain Gnats Effectively


Drain flies belong to a family of real flies and have tiny, hairy bodies with wings. So, they have a “furry”, moth-like appearance, which earns them the name “moth flies”. Their other names include sewer flies, sewer gnats, sink flies, and filter flies. Drain gnats belong to the sub-family Phlebotominae, which feeds on blood (hematophagous). In some regions, these flies are known as sand flies, but this term also applies to other unrelated flies.

There are over 2,600 known species of drain gnats around the world, most of which are native to areas with humid tropics. Therefore, it’s an extremely diverse family of this order. As their name suggests, drain gnats are predominantly found in plumbing drains and sewer systems. Although these flies are harmless, they can be persistently annoying when they overpopulate your sink and sewer system.

The larvae of drain gnats live in aquatic, semi-terrestrial, or sludge-based surroundings like bathroom sinks, where they can feed on microbes and populate within a short time. Their larvae are mainly transparent with a non-folding black head. You can see the larvae moving along the humid edges of cracks in your shower stall or bathtub.

Sometimes they are submerged in toilet water and are usually between 4 and 5 mm long. This larval form resembles a long, thin, and flattened cylinder. Its body lacks prolegs, while its segments are divided into several rings known as annuli. Some of the rings feature typical plates on the dorsal side.

Their larval thorax isn’t significantly bigger than their abdomen, so it has a more worm-like look than most of the other insect larvae that thrive in water. Some species have attachment disks on the side of the ventral that help them to cling to the surfaces of sinks and toilet basins. Since the larvae can’t take in oxygen through water, they breathe through their small dark tubes (spiracles) on the end of their posterior.

So, they often have to reach the surface of the water to get oxygen. They stay in their larval stage for about 9 to 15 days before they mature to become drain flies. But this duration depends on the species, habitat, and temperature. Sometimes drain flies are considered to be beneficial because they can cut through the sludge in your drain to unclog blocked sinks.

But as long as the sludge waste remains in the drain or sink, adult drain gnats will find it and lay more eggs, resulting in the overpopulation of sink flies in your house. Adult drain gnats are half as long as their larvae, and they have a broader look, with hairy wings attached to their bodies in a pitched-roof-like style. Adult sink flies live for about 20 days and they only breed once in their lifetime.

They usually breed hours after evolving from their pupal coverings. Female drain flies lay between 30 and 100 eggs above the water line. These eggs normally hatch within two days into drain worms. Although these flies aren’t harmful they can make your house uncomfortable to live in, especially when it’s overpopulated with tiny flies.

That’s why you need to figure out the best way to get rid of the flies for good. Here are the five ways to get rid of drain gnats in your house.

1. Clean Your Drain

As mentioned above, adult female drain flies are always looking for sinks and drainage openings with sludge waste to lay their eggs. Therefore, the first thing you have to do is clean the entire sink and drain and make sure there’s no sludge lying around where the flies can lay their eggs. This is just a simple, ordinary cleaning process with usual cleaning solutions.

For instance, you can use a pipe brush to get everything out of the sink, especially from the hidden parts of the drain where a normal brush wouldn’t reach. The most effective way to chase the flies away and make sure they never came back is to make your sinks and drains as unfavorable to them as possible.

2. Boiling Water

When our sinks and drains are clogged, plumbing experts recommend pouring boiling water into the sink to dissolve the sludge waste and clear the clog. You can use the same trick to remove drain gnats from your sink. Just boils 2 or 3 liters of water and pour it directly into your drain right away to kill the flies and their eggs.

Repeat this process once or twice every week until you are fully satisfied that there are no more drain gnats. Remember to pour some of the boiling water around the drain to make sure you don’t miss any eggs.

3. Baking Soda

Baking soda is good for many applications, including getting rid of drain gnats. Simply mix half a cup of salt with the same amount of baking soda. Add one cup of vinegar, and pour the mixture down your drain.

Shut off the tap and let the mixture sit overnight. In the morning pour a full pot of boiling water into your sink to clear the drain. This will help to eliminate the drain gnats together with their eggs and larvae. Repeat this process once every week until you are fully satisfied that the drain is free of flies.

4. Drain Cleaner

A drain cleaner from a local store will also get the job done effectively. However, this method is a little bit heavier-duty than the other processes indicated above. It involves pouring chemicals into your drain to eliminate drain flies.

The chemicals will wipe everything out, including the eggs, debris, and any other foreign materials. These materials can offer a perfect breeding ground for drain gnats if they sit in there for a long time. However, you need to be careful with the chemicals so you don’t end up damaging your drain pipes.

5. Apple Cider Vinegar Trap

Aside from dressing your salad, you can use apple cider vinegar to trap the annoying drain gnats in your kitchen and bathroom. This trap is based on the concept that the apple cider vinegar smells so sweet that the drain gnats can’t resist tasting it. So, as they fly into the bowl to taste the sweet vinegar, they get trapped inside and drown.

The bowl contains a mixture of apple cider vinegar and dish soap which chokes the drain flies to death once they are trapped inside. You just need a quarter of a cup of apple cider vinegar and a few drops of dish soap. Punch several holes in the bowl’s lid and make sure the lid is tightly fitted. The holes allow the drain gnats to get into the bowl and keep them trapped inside long enough to die.

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