How to Get Rid of Drain Flies

Home drains are a prime spot for stagnant water or bacteria to accumulate, especially if the sink or drain sits unused. If you’ve suddenly noticed an abundance of very small, moth-like creatures hanging around your sinks, showers, or bathtub, you may have drain flies. These very common pests can reproduce in just 48 hours, making it easy to find yourself with an infestation in little time.

Unlike some other pest infestations, understanding how to get rid of drain flies can be quick and simple. With a little diligence, you can stop them in their tracks with basic products or pantry items around the house and create a plan to stop them in the future. In this guide, we’ll answer all your questions about how to get rid of drain flies and who to call if you need the guidance of a professional pest control company.

Drain flies commonly go by a few nicknames such as moth flies or sink flies. They are about the same size as gnats and fruit flies—between 2mm and 5mm—but can be distinguished by their small, moth-like wings and round, fuzzy bodies. Drain flies also differ in color compared to other small house flies, typically ranging between pale gray to black. While they may look like moths, these little creatures cannot fly very far. You’ll notice that they make large hops from place to place instead of buzzing around your home like other pests.

Drain flies have a lifespan of between eight and 24 days but can lay and hatch up to 300 eggs in just 48 hours, so it’s important to get ahead of the problem before they have a chance to spread through your pipes.

Drain flies enjoy stagnant water that collects even small amounts of bacteria and sewage, so they are often found congregating around:

• Kitchen and outdoor sinks
• Shower and bathtub drains
• Basement sinks (especially those that go unused for some time)
• Sewers
• Septic tanks
• Soil that contains sewage

One common denominator among all of these places is low, stagnant water. Drain flies can lay eggs in the film that forms on the inside of pipes and drains when water pools and collects sewage. For this reason, drain flies may also be attracted to:

• Wet mops and buckets
• Compost piles
• Storm drains with standing water
• Wet areas around the garbage, birdbaths, or barns

Drain flies primarily live on organic material found in standing water, which often includes sewage or other contaminated water, typically when it causes a film to build up in a humid area of pipes with standing water. Because of this, your drains are an ideal place for drain flies to thrive and reproduce. They can also find food and sewage near a collection of garbage, animal waste, or compost.

In short, no, drain flies are not harmful to humans. Though drain flies consume and live in sewage and bacteria, they are not disease-carrying insects, but In great masses, they can carry the bacteria with them. Overall, they cause no proven harm to your health, even if they are a serious nuisance in your home. As we noted before, drain flies can also reproduce quickly, spreading nests throughout your pipes that can be costly to clear out if left unchecked.

If you’ve started to spot these tiny moth-like flies around your home, you may not immediately realize you have an infestation growing in your pipes. There are a few sure ways to check if more drain flies are living and breeding in your pipes.

Duct Tape Test

Place a piece of duct tape on top of your drain and seal it off overnight. Drain flies will eventually try to come up to the surface but will get stuck to the tape on the way out. Not only does this take care of some of the flies in your drain, but it can give you an indication of how the infestation has grown. Repeat several nights in a row to fully assess the issue.

Check for Larvae

Drain flies frequently lay eggs in the organic material that builds up right at the opening of your drain. Remove the drain cover, scrape some of the slime off the sides, and look for thin, tube-like, drain-fly larvae. If you don’t spot any here but are certain you have an infestation, this could be a sign that the eggs are being laid deeper within your pipes.

Depending on the degree of your drain fly infestation, you can take a natural or chemical route to get rid of the pests. In many instances, it is possible to quickly get rid of drain flies with common items found in your kitchen or under the sink.

Natural Ways to Get Rid of Drain Flies

In some cases, simply flushing out your drains can remove both the drain fly larvae and remove any temptation for drain flies to return. Use these methods both as preventative and management tactics for managing your infestation.

Boiling Water

The simplest method to clear out your drain fly issue is to pour boiling water carefully down your drain 1-2 times a day for about a week. This will ensure that the flies do not return overnight if the water did not catch all of the organic material built up inside.

Baking Soda + Salt + Vinegar

Combine this go-to mixture of pantry items to create a natural cleaning solution and pour it down your drain overnight. The baking soda expands with the vinegar, reaching more areas than the boiling water. After letting the solution sit until the morning, flush out the pipe with boiling water.

Soap + Water + Sugar + Vinegar

Add a few drops of dish soap to a bowl of water, sugar, and apple cider vinegar. Leave the bowl out for a few days close to the drain to attract the drain flies to the sweet solution. The thickness of the added soap will trap the flies in the water.

Apple Cider Vinegar + Plastic Wrap

Create another common DIY fly trap by covering a bowl, jar, or mug with plastic wrap. Fill the bottom of the container with an inch of apple cider vinegar. Punch small holes in the top of the plastic in order to allow the flies in but not allow them to get out.

Drain + Duct Tape

Use our detection method mentioned above to also eradicate some of your drain fly issues. Seal off your drain with duct tape overnight for several nights in a row to catch the flies that try to get to the surface.

How to Get Rid of Drain Flies with Chemicals

Since drain flies often live in or around your pipes, common cleaners and substances for clearing drains can also get rid of drain flies. When you do use chemical cleaners, always read the instructions, and do not mix them with other chemical or natural cleaning products.

Traditional Drain Cleaner

After flushing your drain with warm water and giving it a pass with a metal pipe brush, you can clean out the remaining residue with products like Drano and Bio-Clean. Be sure to check if it is safe to use these products more than once if necessary and whether they can be used in drains outside of the bathroom.

Chemical Sprays and Repellents

Many common pest control killers, typically for fruit flies or gnats, can also be used to kill drain flies when the pests are listed on their labels. Since many of these contain caustic chemicals, check if you should keep them out of the kitchen area and be extra careful about damage to your drains.

1. Green Gobbler: This popular fly killer is safe to go down drains, septic systems, and even garbage disposals.
2. Natural Armour: This gel-based drain cleaner is ideal for tricky pipes that require an expansive cleaner to catch any additional nests or flies.
3. American BioSystems: Typically recommended for commercial drains, this is an extreme option for clearing bacteria out of drains, specifically when dealing with a drain fly infestation.

Drain flies look for pools of sitting water containing sewage and other organic material. Preventing drain fly infestations requires clean pipes that are frequently flushed out either with water, or in more extreme cases, cleaning solutions on a regular basis. If you have a drain that frequently goes days or weeks without use, close it up with a stopper so that drain flies cannot find a home there in the meantime.

Outside of your drains, keep an eye out for standing water in other areas in and around your home. Never leave dirty mops in buckets of water and be sure you have a healthy septic system.

Always keep an eye out for early signs of an infestation, even if you just see a few drain flies out of the blue. Taking precautionary steps to check and treat a possible problem is essential.

Seasoned professionals can eliminate drain flies quickly and efficiently using proven methods.  We’ve reviewed the nation’s top pest control providers. Here are our favorites for drain fly control based on experience, price, and customer reviews.

Terminix

The Terminix team offers extensive pest control services in all states except for Alaska, North Dakota, and South Dakota. Terminix provides different tiers of plans depending on your needs. This pest control provider has outstanding customer service, flexible prices, and decades of experience.

To get a free quote from Terminix, call the company at 866-569-4035 or fill out this quick form.

Orkin

Orkin has been remediating pest control issues for homeowners across the country for more than a century, available in all states except for Alaska, Wyoming, and South Dakota. The company practices Integrated Pest Management and has excellent reviews.

For a free quote from Orkin, call 877-868-1416 or complete this form.

Frequently Asked Questions

Dealing with persistent drain fly issues and not sure where to start? Here is a recap of all you need to know about stopping the problem before it gets out of hand.

The This Old House Reviews Team backs up our pest control recommendations with a detailed rating methodology that we use to objectively score each provider. We review pest control plans, navigate the provider website, speak with customer service representatives by phone and online chat (if available), request quotes, and analyze customer reviews for each provider. We then score the provider against our review standards for plans and services, reputation and customer responses, customer service offerings, workmanship guarantees, financing, and availability to arrive at a final score on a 5-point rating scale.

To share feedback or ask a question about this article, send a note to our Reviews Team at reviews@thisoldhousereviews.com.