Sewer Flies: How to Get Rid of Sewer Flies?

How to get rid of drain flies

What are sewer flies or drain flies or sewer gnats?

Sewer flies or sewer gnats are also known as drain flies, drain gnats or Phorid flies. They did not get their names by accident. They are called “drain flies" because they breed and feed in the organic matters commonly found in the drains of your sink or bathroom.

The adult drain flies reproduce their larvae on drains. In these types of places, their eggs, feed on grease, sludge, food, hair and anything else found in your typical drain.

In 9-15 days, these eggs will grow into adults and you’ll have more flies in your house before you know it.

Sewer flies are small. Their bodies and wings have short hairs that make them look furry.These flies usually have wings with a shape of a leaf, either broad or slender.

They have long hairy antennae and have a total size of 2mm. They are basically nocturnal, but you’ll see them hanging around on flat surfaces or walls.

What causes sewer or drain flies in your house?

Drain flies exist because there are organic materials found in your bathroom sink, kitchen sink or shower. There are many other reasons that cause sewer flies or sewer gnats to be in your house.

  • Clogged or blocked drain sink causing the food or organic substance stay on top of the kitchen sink
  • clogged or blocked shower drains that creates optimum conditions for the sewer flies to breed and reproduce
  • Bright colors also attract the sewer flies or sewer gnats to your house
  • They are also attracted to strong scent or odor comes from your house.

How to get rid of Drain (sewer) flies naturally?

Not all the flies are same. It’s important that you learn how to distinguish them in order for you to have the proper methods or products to use to get rid of them completely.

To effectively and permanently remove them, you just have to regularly clean out your drains.

Here are simple things that you can do in order to remove these pesky little fliers:

Determine where the problem is. Sewer flies don’t wander far from where they breed, that’s why it’s easier to check all the drains and sinks, both inside and outside your house. To determine which drains are infested, do the following things:

  • Dry all drains at night.
  • Place a strip of tape over each drain, but leave a small space for air.
  • Check the tapes after a day or two if there are flies stuck to it. This will only mean that the particular drain is infested with sewer flies.

Destroy the flies’ breeding ground. Follow these simple steps to get rid of the larvae.

  • Use 1 to 2 gallons of warm water to moisten the drain.
  • Use a metal pipe brush to clean the drain from dirt, grease, food, etc.
  • Use a plumbing snake to get rid of other grime.
  • Pour 4oz of gel drain cleaner into each infested drain. (Let it sink for several hours.)
  • Flush the drain with lots of water and finish cleaning it up with a plunger.

Kill all the adult flies. Use a fly swatter to kill the adult gnat flies and finish it up with an insect spray to make sure that nothing was left behind.

Follow-up. Regularly clean your drains to guarantee that the sewer flies won’t return again. You can also use an insect growth regulator in your drain to kill any larvae planning to spread again.

6 Best Products to get rid of Drain (Sewer) flies

Though there are wide range of products available in the market to get rid of drain flies but only a very few actually works on killing drain flies and getting rid of them from your house.

We have choosen the best drain fly killing pr​oducts and also few best products to clean your drains further avoiding the re-infestation of drain flies

1. Brushtech Extra Long Super Flexible Drain Brush 

Drain flies breed inside your drain pipelines and they feed themselves from the clogged organic substance in the pipe.

First step to get rid of drain flies is to eliminate their breeding source and stop feeding them.

Brushtech Extra Long Super Flexible Drain Brush

Brushtech extra-long drain brush is flexible enough and it bends through the piper to clear the blocking hair, bad odor causing gunk and blockages.

It goes in deep inside the drains to get rid of tough blockages and improves drainage flow by clearing the blockages.

Things we liked

  • Very effective when it unblock deep drains
  • Can clean on the sides of wall

Things we don't like

  • Cannot work when the drain pipe is not linear

2. Drain Gel - 1 Gallon (Drain Fly Control)

When you want to get rid of drain flies then drain gel is the final effective solution to treat drain fly problem when all the ordinary drain cleaners, pouring hot water, bleach or ammonia is ineffective in killing drain flies or sewer gnats.

Drain gel is made up of specialized microorganisms combined with biological support ingredients and essential growth factors.

It not only cleans the drain moss but also prevents the drain fly eggs from hatch when it gets contacted.

It reaches deep inside the drain and removes hard to reach organic matter from drains where the sewer flies breed on feed the organic matter.

This specially formulated drain gel coats inside the drains and pipes that it may continue to work for several hours and not just washing away like any other product.

Drain gel will also get rid of rank odors from drains and improves the flow of slow drains.

Drain Gel to get rid of drain flies

Things we liked

  • Great for Drain Fly treatment program, but not labelled to kill Drain Flies.
  • Removes Organic Material and Grease from Drains, Cracks, and Crevices.
  • Safe for all Plumbing and Septic Tanks
  • Removes Organic Material From Drain Lines and Non-Drain Areas
  • non-toxic, non-pathogenic and non-caustic

Things we don't like

  • Takes long time to work

3. Gentrol Insect Growth Regulator (IGR) 16 oz can

This product uses hydroprene active ingredient that prevents the pest larvae turning into adult stage either by causing sterility of adults or preventing the emergence of insects from pupal stage thus preventing the future flies infestations.

Genrol Aerosol applied on pest active area provides pest control for up to 4 months.

This product is in foam nature and dissipating the foam virtually eliminates any change of missing any area.

Gentrol insect grow regulator has to be applied regularly inorder to get rid of sewer flies

Gentrol - Drain Fly killer foam

Things we liked

  • Control Roaches, Stored Product, Pests, Drain Flies, Fruit Flies and Bedbugs
  • Non-RepellentLong-Term Control
  • Compatible in baiting programs
  • Treats up to 1200 square feet

Things we don't like

  • Strong Smell

4. Best Drain Cleaner & Septic Tank Treatment - 2-in-1

Clogged Drains is the main source of sewer flies breeding. Household wastes may also clog the drain pipes in your home and these wastes will continue to pile up ove a period and slowly it shrinks the flow and resulting in odor.

Also, it invites the sewer flies to come and infestate in the drains.

This product removes all the problems the you suffer with your dains i.e bad odor and sewer flies.

The usage of this drain cleaner is very easy, simply mix 1 fluid ounce of the solution with 1 gallon of warm water, stir it well and pour 8-16 fluid ounces down every household floor drain, sink drain, shower drain and garbage disposal.

Natural Rapport Drain Cleaner and Septic Tank Treatment

Things we liked

  • Easy to use.No Messy Powders Left In Sinks Or Toilets After using
  • Concentrated Drain Cleaner formula.
  • Each Dose Treats Up To 1500-gallons Of Septic Tank Capacity
  • Eliminates odors and Problem-Causing Fats, Oils, Greases, Tissue Paper, Hair, Human Wastes and More
  • Non-Toxic, Non-Caustic - Safer for Plumbing and Use Around Kids, Pets & Plants

Things we don't like

  • Doesn't break down the hairs well

5. Fly Web Trap

This product helps to get rid of gnats, flies and other flying insects with using toxic and harmful chemical in this plug-in device.

This device can be used with any AC outlets and it uses 9 watt UV light bulb to attract sewer flies within 600 square foot.

The sewer flies are attracted towards the bright light and when they get contacted they are trapped with the sticky adhesive glue board.

This product is designed only for indoor usage.

fly Web Fly Trap

Things we liked

  • Very effective when it comes to trapping the flies
  • Works as your source of light at night
  • Won’t disappoint you every night
  • Very effective for indoor use
  • Covers 600 square foot area

Things we don't like

  • The pack comes with only one glue board which is easily filled in just one night.
  • Only works at night or in dark rooms
  • Trapped flies will tend to buzz all night

6. OXO Good Grips Easy Clean Shower Stall Drain Protector - Stainless Steel & Silicone

As said in the beginning, Clogged drains are the one of most common reason to have sewer flies in the house. This OXO Good Grips shower stall drain protector solves the problem of clogged drain. 

This product is made up of rust-proof stainless steel, it sits on top of the shower drains and the hole pattern is designed in such a way to catch the hairs without blocking the water drainage.

The drain protector plays a major role in preventing the drain fly infestation by preventing the clogging.

It is kept in place by a silicone rim which prevents the sliding.

OXO Good Grips Easy Clean Shower Stall Drain Protector

Things we liked

  • Design is simple, but very effective
  • Grips and protects your drain
  • Very easy to clean
  • Silicone rim for proper placement
  • Catches hair in your shower to prevent sewer flies

Things we don't like

  • When accidentally kicked, it moves around
  • May not fit in other shower drains (measure first before buying)


The above are the well known and effective products to get rid of drain flies when the natural ways of pouring hot water or ammonia doesn't work.

We constantly strive to keep this post updated with all possibly ways that helps you to get rid of sewer flies from you home quickly.​

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