Discovering some unwanted houseguests skipping around your kitchen or bathroom isn’t fun. They could be drain flies and, luckily, are simple to get rid of.
To get rid of drain flies, try pouring boiling water down your drain once per day for three days or more. You could also try putting vinegar, bleach or a strong drain cleaner into your pipes. Maintaining clean drains prevents these insects from returning.
When it’s all said and done, drain flies are nothing to panic over. In the rest of this article, I will give you detailed instructions on getting rid of these insects, how to identify them and ways to stop them from coming back.
You might also be interested in reading this related articles: “Fly Identification Table Summary – Adult Occurrence, Host Material and Life Cycle” and “What scents will keep flies away?“
Getting Rid of Drain Flies
Fortunately, you can employ many effective natural or chemical methods to get rid of drain flies. In fact, you might already have some of the ingredients to eliminate these insects in your cupboard.
Getting Rid of Drain Flies Naturally
For an underused drain, simply setting a routine to use it could eliminate the drain fly problem. Otherwise, there are some ways you can get rid of these insects without turning to harsh chemicals.
Boiling Water
Pour two quarts of boiling water into your drain. Then, repeat that action for four days to a week. The boiling water should kill drain flies, eggs and larvae and clear some organic matter from the pipe.
How To Get Rid Of Drain Flies With Vinegar
Vinegar is a highly acidic liquid that kills drain flies, their eggs and their larvae. Pouring white vinegar into your drain each night for three days should kill the insects inside.
Bubbly Drain Fly Killer
For extra power, pour white vinegar and baking soda one at a time into your drains, letting them mix inside, and they will bubble up and work to kill the drain flies. You don’t need to use so much that your drain turns into a messy volcano, just enough that the bubbles reach both ends of your P trap.
Add these compounds before bedtime, and let them sit in the drain overnight. Repeat this process for two or three nights to kill the drain flies while cleaning your pipes.
Easy Drain Fly Trap
Mix water, sugar, apple cider vinegar and dish soap in a bowl. The drain flies will be attracted by the sugar and vinegar smell, but then the sticky soap will trap them, and they will drown.
Leave the bowl out for a few days to a week. Be sure all of the drain flies are dead before disposing of them.
Plastic Wrap Drain Fly Trap
For this drain fly trap, fill a jar, mug or bowl with half an inch of apple cider vinegar and cover it with plastic. Poke small holes in the plastic, and the drain flies will get in to taste the vinegar but won’t be able to fly out.
Chemical Ways to Get Rid of Drain Flies
Common drain cleaners also work to eliminate drain flies. If you decide to go this route, wear personal protective equipment and never mix cleaners.
Follow all of the instructions on the product you choose. Drain cleaners are highly corrosive and may not be suitable for repeated use if the first pass doesn’t kill the drain flies.
Will Bleach Kill Drain Flies?
Yes, a cup of chlorine bleach poured down the drain will kill most drain flies, eggs and larvae. One treatment should be enough, but you could make additional treatments to ensure it works.
Sprays and Repellents For Drain Flies
Most traditional pest sprays and repellents work for drain flies. You might look for products specifically for drain flies at your local hardware store.
Always follow the instructions on bug sprays and repellents. They can be harmful to your skin, eyes or pets.
Identifying Drain Flies
You may know drain flies as moth flies or sink flies because they look like tiny moths and hang around sinks. They are two to five millimeters long, or about the size of a fruit fly, but have moth-like wings and furry bodies.
Despite their physical similarities, drain flies aren’t good flyers like moths. In fact, you’re more likely to see them hopping around your house than buzzing.
You can distinguish drain flies from house flies by their color, which is tan, pale gray or pale black. If smashed, a drain fly leaves behind a powdery-looking spot from its dense coat of fine hairs. A close-up view of a drain fly shows that it has two furry antennae on its head, which are absent in other small flies.
What Is Causing Drain Flies?
The cause of drain flies in the house is humid conditions that allow them to breed. Furthermore, some of the most common causes of drain flies are:
- Dirty drains
- Leaking pipes
- Broken septic tanks
- Overwatered houseplants
The film that forms inside pipes is a perfect host for drain fly eggs. Frequently, these insects are caused by a little-used sink or shower, such as in a basement or guest bathroom.
Household drains have P traps, which hold water inside themselves to stop sewer gases from coming into the house, but could also attract insects. If you don’t use a drain often, the P trap sits full of stagnant, dirty water, which is a perfect breeding site for drain flies.
Drain Fly Diet
Drain flies feed on organic matter found in standing water. Some of the items these insects might be feeding on in your home include:
- Food scraps
- Dead skin
- Sewage
- Oils
- Grease
- Bodily fluids
As you can see, you will inevitably have some drain fly food in your home. Therefore, regular sink and drain cleaning is the best way to eliminate these food sources.
Also, using a kitchen sink garbage disposal could create an excellent food source for these insects. In the end, reducing the scraps you put down the kitchen sink could help eliminate drain flies.
Drain Fly Lifecycle
Understanding the lifecycle of drain flies can help you get rid of them. The drain fly lifecycle includes:
- The egg stage, lasting about 48 hours.
- Next, the larvae spend a week to 24 days eating and growing.
- Then, the one to two day pupal stage where the worm-like larvae transforms into a winged adult.
- After two days as an adult, a female can lay 30 to 100 eggs at a time in a dark, wet place with access to organic material to start the cycle again.
You might notice many drain flies appear suddenly because a wandering female laid her eggs in your home. Acting fast to clean your drains could prevent more drain flies from developing and causing further problems.
Are Drain Flies Dangerous To Humans?
No, drain flies are not dangerous to humans. Despite their close association with sewage, they don’t carry any diseases or bacteria that can spread to people.
Actually, drain flies could be beneficial to your plumbing system. They clear away some bits of organic material from drains that could eventually build up and cause a blockage.
In the case of large drain fly infestations, their tiny hairs could irritate a person’s lungs. This problem could be worse for someone who suffers from a lung condition.
How To Tell If I Have A Drain Fly Infestation
Seeing one or two drain flies in your home doesn’t mean you have an infestation. Two ways to check if you have a drain fly problem are:
The Tape Test
Seal your suspicious drain with duct tape overnight when you don’t need to use it. If drain flies are living down there, they will get stuck to the adhesive when they try to leave.
If you catch drain flies in this test, there are probably a few hundred eggs in your drain. Their lifecycle will continue until you take action to stop them.
Look for Larvae
The slimy layer of gunk under your drain cover is a perfect habitat for drain fly larvae to grow. For this test, remove the drain cover, scrape out some slime with a knife, and look for tiny worms.
If you don’t see larvae at the top of your drain, they could be deeper in the pipe. At this point, it’s a good idea to give your drain a good cleaning, whether you find drain flies or not.
How to Prevent Drain Flies
Drain flies are attracted by pools of stagnant water containing organic material. Following that train of thought, keeping your drains clean and frequently flushing them with water helps prevent these insects from living in your home.
For drains that don’t get much use, put a stopper on them between uses to shut flies out. Alternatively, add salt, bleach or vinegar to the drain monthly.
Additionally, clean the outside of your home, patch cracks or holes that insects could enter through, and eliminate standing water from your property. Lastly, leaking pipes, gutters or septic tanks should be fixed promptly.
Should I Hire Pest Control For Drain Flies?
Because drain flies aren’t dangerous, you can try eliminating them yourself. If your attempts fail, you may need the help of professionals.
While a pest control expert could help you with drain flies, the better helper might be a plumber. A persistent drain fly infestation is likely due to a problem in the plumbing system.
A plumber can help you identify the source of the problem and how to solve it. Unfortunately, you may have a broken sewer line under your house that needs to be dug up and replaced.