Get Rid of Drain Flies

If swarms of small flies have suddenly sprung up around your kitchen sink, bathroom sink, or shower, you may have a drain fly infestation. This article will teach you how to get rid of these pesky pests.

10 Second Summary

1. Clean the hair catcher, if applicable. More ↓
2. Moisten the drain with water, if needed.
3. Clean the drain with a metal pipe brush.
4. Fish out other grime with a plumbing snake.
5. Pour a gel drain cleaner into the drain.
6. Finish up with a plunger.

Steps

Identifying the Problem

  1. Identify the problem areas. 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.
  2. 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.
  3. Place a strip of clear tape over each drain. Stick the tape over the center of each drain with the sticky side facing down.[1]
    • Do not completely cover the drain with tape. A covered drain will prevent flies from flying up, leaving you with no evidence.
  4. 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.

Destroying the Breeding Ground

  1. 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.
  2. Moisten the drain, if necessary. Pour 1 to 2 gallons (4 to 8 liters) of warm water into the drain to moisten it slightly.
    • Note that this is only needed if the drain is not used on a regular basis. Drains used on a daily basis are moist enough without taking additional measurements.
  3. Use a metal pipe brush.[2] 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.
  4. 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.
  5. 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.[3]
    • Vinegar, boiling water, and bleach are traditional remedies for getting rid of drain flies, but many experts insist that these methods are not effective.
    • Baking soda and vinegar poured down the drain may kill the flies; it will clean the drain at least.
    • You may need to repeat the same dosage of drain cleaner once a day for five to seven days total.
  6. Finish up with a plunger.[4] 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.

Killing Adult Flies

  1. 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.
  2. 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 (305 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.

Follow-Up

  1. 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 to increase this to once every one or two weeks.
    • A thorough cleaning is not necessary. Simply pour 4 oz (125 ml) of gel drain cleaner into the drain and let sit 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.
  2. Apply insect growth regulator. Spray an aerosol IGR directly inside the drain and along the drain lines.
    • IGR prevents drain flies from breaking out of the larvae stage. Since flies only breed once they enter the adult stage, this greatly reduces the number of flies breeding, thereby cutting down on future infestations.

Things You'll Need

  • Clear tape
  • Metal pipe brush
  • Plumbing snake
  • Gel drain cleaner
  • Plunger
  • Fly swatter
  • Space spray
  • Insect growth regulator

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Sources and Citations

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