drain fly

Help!!! How Do I Get Rid of Drain Flies?

Drain flies are pesky insects that tend to congregate around standing water, and are a common nuisance in many homes.  Also known as moth flies, sewer flies, and filter flies. Contrary to what their name suggests, they actually don't "fly" very well, but rather travel with little hops and jumps from surface to surface. Drain flies can live for up to three weeks, and new eggs can hatch every 48 hours, so as with all potential insect problems, you should act fast. These pests live and breed inside your plumbing pipes, feeding on decomposing material and laying eggs within the gelatinous slime that collects along the interior walls of your drain. Adults can be spotted resting on walls and ceilings of the infested areas.

Physical Appearance: Measuring in at just 2 to 5 millimeters (about one-eighth

drain fly

of an inch),light grey or tan colored flies with a short body and leaf-shaped wings.

The body and wings are covered with small hair which gives it a fuzzy appearance. Their wings are too large when compared to the body.  They fold their wings in a characteristic roof-like pattern. 


Life Cycle: The length of the life cycle of a drain fly varies depending on the climate and temperature of the drain, but it can last anywhere from eight to 24 days. The adults can be spotted resting on walls and ceilings of the infested areas. And as these flies are not good at flying so their source i.e. (breeding area) is very near to the infested area.

 So, when you spot some adult drain flies, find a nearby pipe or a drain. The drain or the pipe will be acting as the breeding source for these flies. In case there are multiple pipes or drains near the infested area then you may need to use the second method to find the actual breeding source.

Drain flies lay eggs mostly in decomposing organic matter found in drains and pipes. The eggs are brown or cream in color and hatch in 32 to 48 hours. The larvae feed on the gelatinous drain matter and reach the maturity age in 9 to 14 days. Drain fly larvae are known to survive in high temperatures and low oxygen conditions.

Damages: Drain flies can grow quickly and hence they can multiply in a few days creating a nuisance for you.

Though drain flies are not reported to transmit any diseases to humans, they are capable of doing mechanical contamination of foodstuff as they originate from a filthy source. They can intensify bronchial asthma in some people.

 While these insects don’t bite or spread disease, no one likes to see tiny, winged bugs flying out of otherwise clean sinks. If you see some hanging around your kitchen or bathroom, follow these steps to identify the source of drain flies and eliminate them.


Drain flies thrive on stagnant, shallow water, especially near sources of food or bacteria, like sinks and showers. They often favor areas that have been left untouched for a period of time, or are generally not used frequently. (Many people spot them in a seldom-used basement or workshop sink, or after returning from a significant vacation or time away from home.) They thrive on moisture and organic debris (notably different from fruit flies, which thrive on fruits and vegetables) and can even pop up in a relatively clean area.


Dry all the drain areas before going to bed. This is the first thing you must do to verify that the problem is coming from the drain itself. You might actually be infested by another type of fly drawn in by rotting fruit or other food sources. As a result, you should verify that you actually have drain flies in your drain before taking measures to remove them.

Tape Test: If you spot one or two, try this overnight test: Place 

Drain Fly Tape Test

pieces of tape (sticky side down) over the drain in question. As they try to escape, they will become trapped on the tape, and you'll have a good indication of just how many flies you're dealing with.  Do not completely cover the drain with tape. A covered drain will prevent flies from flying up, leaving you with no evidence. 

Check the tape in the morning or after a few days. If you spot flies on the tape after removing it from the drain, drain flies are the most likely culprit. Even if you do not find any drain flies on the tape after the first night, you should repeat this process for at least four nights to account for discrepancies in the breeding cycle.


STEP 1: Identify affected drains.

Before you can rid your home of drain flies, you need to identify the affected drains. Adult drain flies love to feed and breed in slow-moving or clogged drains, because they provide plenty of decomposing material where the insects can complete their life cycle. If any of your drains are backed up, chances are that those are the root of the problem.  Examine all the drains in your home and any area inside or outside the home that has standing water. Any area with multiple drain flies is likely a problem.

Luckily, drain flies do not stray far from the place they have chosen to make their home, so it is rare for a drain fly infestation to spread to all areas of the house. This is especially true if you catch the problem early.

STEP 2: Clean affected drains. 

Once you’ve determined which are the problem drains, you need to clean out

the slimy gunk that has collected there in order to eliminate the flies’ breeding zones. Resist the urge to pour a bottle of chemical drain cleaner down the drain immediately as that won’t effectively take care of all the decomposing material in your home’s pipes and traps.

Clean the hair catcher, if applicable. Remove the hair catcher or filter from an affected shower drain and clean it out thoroughly, removing all the hair tangled inside it. The key in destroying the drain fly's breeding ground is removing all hair, grime, and debris that the flies might lay their eggs in.

Moisten the drain, if necessary.  If the drain is not used on a regular basis pour 1 to 2 gallons (4 to 8 liters) of warm water into the drain to moisten it slightly. Drains used on a daily basis are moist enough without taking additional measurements.

Use a metal pipe brush. Work a metal pipe brush into the drain, extending it as far down into the drain as possible. Twist the brush while slowly moving it up and down to remove grime from the sides of the pipe.

Fish out other grime with a plumbing snake. Insert a plumbing snake into the drain and twist it through the pipes to pull out clumps of grime that lie further down.

drain fly repellant

Clean and Clear the U Trap: Open the U-trap under your sink so you can easily reach and remove any other clog-causing remnants that have collected inside.

Pour a gel drain cleaner into the drain. Apply roughly 4 oz (125 ml) of the cleaner around the edge of the drain.

Applying the cleaner to the edge of the drain allows it to coat the sides of the drain and pipe as it glides down.

Gel cleaners are formulated to remove organic matter. You could also use enzyme or bacterial drain cleaners to remove organic material.

 Many people say that instead of drain cleaning gel you could also use boiling water and bleach, these are  traditional remedies for getting rid of drain flies, but many experts insist that these methods are not effective, because drain fly larvae can survive under high temperatures. While baking soda and vinegar poured down the drain may not kill the flies it may help clean the drain.

You may need to repeat the same dosage of drain cleaner once a day for five to seven days total.

Finish up with a plunger.  After the drain cleaner has sat in the sink for several hours, flush it through with plenty of water. Use a plunger to remove any remaining organic matter trapped in the sink.

STEP 3: Kill Adult Flies

Use a fly swatter to kill adult flies. Go to the drain area and squash as many of the drain flies as possible with a standard fly swatter.

While destroying the breeding grounds will prevent the flies from laying more eggs, you'll still have to deal with adult drain flies up to 20 days after you clean the drains. As such, you may want to take extra measures to get rid of as many as possible.

Apply a space spray. If a fly swatter is inefficient, treat the infested area with an insect spray that works in confined spaces.

Close all the doors and windows in the space.

Spray the insect poison upward for 5 to 8 seconds per 1000 cubic feet (28 cubic meters).

Leave the treated area and keep it closed for 15 minutes or more.

Open all windows and doors after returning to the area. Run an electric fan, if possible, to help disperse any remaining spray.

Reapply as often as once every week.

Step 4: Keep the drains clean.

You should clean the drains in your house at least once every month, but if you've already had problems with drain flies, you may want

Drain Flies

to increase this to once every one or two weeks.  A thorough cleaning is not necessary. Simply pour 4 -8 oz (125 ml) of Repel Drain Fly into the drain and let sit overnight to maintain a continual state of cleanliness.

For drains that are rarely used, such as in a garage or basement, pour a little mineral oil down the drain. This will prevent further infestations until water is run down the drain.

Apply Repel Drain Fly KillerApply the product at the time of lowest drain usages, typically at the end of the day. Initially add about 8 ounces to each drain. While pouring, try to coat side surface areas inside the drain pipe. Repeat daily as necessary until desired results are achieved. Apply 4-8 ounces per week as a maintenance dosage.

STEP 3: Clear the U-trap.

Use enzyme drain cleaner: Once you’ve cleared out the gunk, close the system back up and pour an enzyme drain cleaner down the drain to attack any remaining residue that didn’t come off with the pipe snake or brush. This specially designed gel has the additional benefit of coating the inside walls of the pipe to prevent future blockages. Let the gel sit in the drain for several hours, according to the instructions on the label, then run more water down the drain to flush it out.

Use a Liquid Dish Soap Spray. Dish Soap contains borax, which has insecticidal properties. You could add 7 drops of dish soap with 2 cups of warm water and spray it directly over the drain flies to kill them instantly.

Set up a Sugar and White Vinegar Trap for Drain Flies. Take a cup and add ¼ cup white vinegar and ¼ cup sugar. Add 5 to 10 drops of dish soap. Leave the cup overnight, and the next morning you would see a lot of dead drain flies in the cup.

Keep Fruit & Drain Flies from Returning:

To ensure that drain flies do not return to your home again, follow the below tips:

  1. Keep the drains clean and clog-free.
    Repel Drain Fly
  2. Make sure that there is no stagnant water in your bathroom or kitchen.
  3. Occasionally Apply Repel Drain Fly to greatly reduce the chances of any future infestation.

Hope you will find these methods useful and remember if the problem is severe then you may need to seek some professional help.