How to Get Rid of Drain Flies: Tips and Tricks from a Plumbing Expert

Say goodbye to these pesky critters and hello to a cleaner home! In this article, we’ll discuss how to get rid of drain flies using anything from natural remedies to chemical treatments. We’ll also explore how to spot the source of the infestation and how to prevent future occurrences. So don’t have a meltdown – with a little know-how it’s easy enough to get rid of those pesky bugs!

Dealing with Drain Flies: Expert Advice & Tips

Close up of a drain or moth fly
One drain fly is kinda cute, hundreds of ’em not so much!

Are you dealing with a dreaded drain fly invasion? While these tiny critters aren’t particularly dangerous to our health, they can spread bacteria and other contaminants. These pesky pests, aka sewer gnats, moth flies, or filter flies, lurk in places where organic matter builds up making the damp environments found in clogged drainage pipes, septic tanks, or sewage systems the perfect breeding grounds for them!

However, there are plenty of simple and cost-effective methods available to ensure your home is safe from these unwanted house guests. Check out this article for some expert advice on how to prevent them from taking up residence in the first place, as well as effective ways of getting rid of drain flies once and for all.

Get Rid of Drain Flies: Key Takeaways 

  • Identify the source – The first step to get rid of drain flies is to identify signs that indicate an infestation, then you can treat and eliminate the problem.
  • Natural remedies – To get rid of sewer flies the old-fashioned way you can try various items you may already have at home, including baking soda, salt, vinegar, apple cider vinegar, and plain old dish soap. 
  • Need something stronger? – You can try chemical or biological drain cleaners, insecticides, or ultraviolet light traps.
  • Prevention is better than cure – Taking steps to prevent an infestation is far easier than getting rid of one. Keep drains clean and free of any organic matter that might attract these pests in the first place.

Natural Remedies to Get Rid of Drain Flies

When dealing with an infestation, there are several natural remedies that can help get rid of the problem. We’ve listed the most effective below:

1. Boiling Water

The simplest method is to pour boiling water into the drainage area where they are breeding. This will kill any adults, as well as any larvae that have accumulated in your pipes. Do not do this, however, if you have PVC pipes as the boiling water can actually crack them!

2. Baking Soda, Salt, and Vinegar

Mix 1/2 cup baking soda with 1/2 cup salt and then pour the mixture down the affected drain. Next, pour down 1 cup of vinegar and leave overnight before flushing out with hot water. The chemical reaction between the two causes fizzing that then breaks down the organic matter your uninvited house guests have been bedding down in.

Baking soda in drain with person pouring vinegar on top to make it fizz
Say goodbye to pesky drain flies with this natural solution!

3. Apple Cider Vinegar + Plastic Wrap

Simply fill a small bowl or jar with apple cider vinegar and then tightly cover the opening with plastic wrap. Poke small holes into the wrap, these will allow the flies to enter but not escape. This method works on the premise that sink flies are attracted to vinegar and will drown when lured into the trap. Place the bowl near the affected drain(s) and let them sit overnight. 

5. Soap + Water + Sugar + Vinegar

Another simple fly trap is to heat up sugar water in a pot until all the sugar dissolves into a syrup. Then add a few drops of soap (to break the surface tension) and some white vinegar (to attract any flies, including fruit flies), stir, and then pour into shallow dishes or cups. Place these traps wherever you see these pesky critters gathering.

Chemical Remedies to Kill Drain Flies

1. Chemical Drain Cleaners

Made from caustic chemicals such as sodium hydroxide or sulfuric acid, this type of cleaner should only be used sparingly, and as a last resort. These chemicals quickly break down and dissolve any organic material that may be clogging the pipes and harboring an infestation. They also kill any insects on contact.

Due to the strong, caustic nature of these cleaners, always follow the manufacturer’s instructions and take any and all proper safety precautions, such as wearing gloves and eye protection. Additionally, if these products are used excessively they may damage your pipes over time.

Gloved hand pouring chemical drain cleaner down the sink
Always protect your hands when using chemical drain cleaners.

2. Insecticides

Another chemical method effective in killing adult drain flies and their larvae is insecticides. You can find insecticide sprays specifically designed for use around drains at most home improvement stores.

As with any chemical spray, make sure to read the label carefully before applying an insecticide. Avoid spraying directly into drains or onto surfaces where food is prepared or stored.

3. Biological Drain Cleaners

If you prefer not to use harsh chemicals, you might consider trying a biological drain cleaner instead. These products contain live bacteria that break down organic matter in your pipes without damaging them.

Biological cleaners work slowly over time but are an eco-friendly alternative to traditional chemical cleaners. They’re not as effective at killing drain flies compared to other methods, so you may need to pair them with another solution.

4. Ultraviolet Light Traps

Another option to combat those drain flies is with an ultraviolet light trap. Victims are lured in by the UV light and then become permanent residents when the adhesive surface traps them there.

Find one near you at a local hardware store or online, then simply place them strategically near areas where you’ve noticed large numbers of drain flies and insect activity.

Portable ultraviolet light trap for flies
Why use chemical pest control when you can use the power of UV technology?

What Are the Signs and How to Identify the Source of an Infestation

The first step to eliminating a drain fly infestation is being able to identify the signs that you have one! Some of these include:

  • Seeing small, dark-colored flies hovering around your sink or shower drains
  • Finding dead ones in and around your drains
  • Noticing a foul odor coming from your plumbing fixtures

One trick to easily check is to stick duct tape over a drain overnight and see if any of the pesky pests have stuck to it by trying to leave at nighttime.

Once you have identified that you’re dealing with an infestation, it’s important to find the source so you can effectively treat and eliminate the problem. Here are some tips for identifying the source:

  1. Inspect your drains: Start by inspecting all of your sink, shower, and floor drains for any visible signs of larvae or pupae. These insects typically lay their eggs on organic debris that accumulates in drains. See our FaQ for a description of what to look out for specifically!
  2. Look for standing water: Drain flies thrive in moist environments, so look for any areas where water may be pooling or not draining properly. The cause of this may be clogged pipes or leaky plumbing fixtures.
  3. Check garbage disposals: These are another potential breeding site as they often accumulate food waste debris.
  4. Inspect outdoor areas: If you have outdoor plumbing fixtures such as garden hoses or sprinklers, check these areas as well for any signs of standing water or dampness.
  5. Contact a plumber: Still having trouble finding the source of the infestation? Then it’s time to call in the professionals. After a thorough inspection, a plumber can advise on how to best treat the issue.

Using these steps to identify the source of your uninvited house guests, you’ll be better equipped to get rid of the infestation and even recurrences of the problem in the future.

Mold around bath tap and in grout in tiled wall behind
Mold growth near plumbing fixtures could be a sign of excess moisture due to leaks or poor ventilation.

Prevent Drain Flies in the Future

Preventing an infestation is far easier than getting rid of it! Here are some preventative measures you can take:

Clean Floor Drains and Dry the Floors

Floor drains, especially rarely used ones, can become a breeding ground for drain flies. A simple blend of hot water, bleach or vinegar will do the trick nicely – but don’t let all that hard work go to waste afterward. Make sure you thoroughly dry up those floors so there are no traces of standing water left for the bugs to find their way back in!

Clean Indoor Garbage and Recycling Areas

Garbage disposals, trash cans, compost bins, and recycling containers should all be kept clean to prevent attracting unwanted guests. It’s also good practice to give any recyclable containers a quick rinse to make sure and remove any residual food or drink debris before throwing them away in the recycling bin. This way you can be sure that there is no leftover food or drink debris that would otherwise make for an irresistible invitation!

Eliminate Standing Water

Since stagnant water is the ideal breeding place for many a pest it’s best to stem any sources of it asap! Make sure any leaky pipes or dripping faucets are fixed up right away; even tiny droplets will eventually accumulate over time to create a pool of stagnant water. So don’t let your place become their new favorite spot to hang out – keep it dry!

Close up of dripping faucet
Even small drips can accumulate over time, creating a pool of stagnant water.

Eliminate the Eggs and Drain Fly Larvae

If you’ve recently had an infestation, it’s important to eliminate any remaining eggs or larvae that could hatch later on. 

Pouring boiling water down your drains will kill off any remaining larvae while removing excess organic material that may have accumulated there. Plus, installing mesh screens over those pipes will make for an extra line of defense against future infestations by blocking off access for adult females looking for places to lay their eggs. 

By following these simple preventative measures, you can significantly reduce the risk of future infestations in your home or rental property.

How to Get Rid of Drain Flies: Final Thoughts

Ready to bid farewell to those pesky flying pests? Before anything else, you’ll need to pinpoint the breeding ground source of the issue. Once located then choose your weapon wisely! For chemical solutions just make sure you read up on any safety precautions first. But remember, when it comes to dealing with drain flies, prevention is far easier than elimination. So be sure to proactively keep on top of things like regular drain cleaning and repairing leaky pipes for added peace of mind!

If you found this article helpful, or have any extra tips or personal experience in defeating the dreaded drain fly, feel free to leave a comment below!

Dealing With a Drain Fly Problem FAQ

What do drain flies look like?

Suspecting drain flies? These mini moths measure around 1/8 inch in length, with gray or black fuzzy bodies and wings covered with translucent scales giving them the appearance of having lighter-colored spots. When they’re done flying around they’ll rest using their wings to make a makeshift roof over themselves – kinda cute! 

If you begin seeing these little critters buzzing around your drains or finding tiny worms poking out – that’s a sure sign that you’ve got an infestation on your hands.

Close up of drain fly
Kinda cute up close, right?

Are drain flies harmful?

Wondering if drain flies are actually harmful? Well, thankfully not to us humans – but they can be a sign of plumbing issues like clogged or leaking pipes. Since they lay their eggs in organic matter, such as hair or food particles that accumulate in drains, it’s important to regularly clean and maintain your plumbing system to prevent infestations. But should the problem persists – it might be time to call in an expert.

Do drain flies bite?

While these tiny insects may be a nuisance and an indication of plumbing issues, they do not bite humans. However, it is important to address the underlying plumbing issue causing the infestation to prevent further problems.

What Do Drain Fly Eggs Look Like?

These eggs are tiny, measuring only about 0.5mm in length, and often resemble small grains of rice. They are usually laid in large groups on surfaces that are moist and organic, the slime layer that forms within drains or on other decaying organic material found in pipes is ideal! 

Drain flies can lay up to 300 eggs at a time, which hatch into larvae within 32–48 hours making it essential to address an infestation at its source before it becomes more severe. The larvae take between 8 to 28 days to fully pupate into adults.

Where do drain flies lay eggs?

If you’ve got drain flies then you should assume there are some eggs somewhere too! Organic matter, such as the decomposing waste that accumulates inside drains or pipes, offers them the perfect moist environment to lay their hundreds of eggs – and quickly! 

Drain fly beside slime where larvae will incubate
Larvae thrive in the slimy gunk that can gather in plumbing pipes.

To keep them from hatching and becoming adults it’s important to regularly clean out any debris or gunk in these areas, including kitchen sinks, bathroom basins, showers/tubs, and toilets.

A long-handled pipe brush or drain snake should dislodge any stubborn build-up while pouring a mixture of warm water and vinegar down the drain can help dissolve any remaining organic matter where tiny white larvae may be hidden.

About the author

An accomplished plumber with more than 15 years of experience in the industry, David "Fitz" Fitzgerald began as an apprentice and steadily worked his way up to become a fully licensed and certified master plumber.

With extensive training in all aspects of plumbing. David is well-versed in the installation, repair, and maintenance of plumbing systems, including pipes, fixtures, and appliances, and is able to troubleshoot and solve even the most complex plumbing issues.

He loves to share his wealth of knowledge and looks forward to engaging with the community here on No Hassle Plumbing.

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