How to Get Rid of Drain Flies

Drain flies thrive in moist environments and areas immediately surrounding sewage treatment facilities. They may also be referred to as sewage or moth flies. They are capable of spreading disease and may appear from time to time inside of the home, climbing out of drains in the sink and tub. The drain fly has a moth like appearance and a tan colored body which is densely covered in long hairs, giving it a slightly fuzzy appearance. It's about 2 mm in size with black or brown wings. Because of its relationship with drains, it's often mistaken for the fruit fly or the phorid fly.

Getting Rid of Drain Flies

Drain flies do not enter the home through pipes. Instead they may get inside through open doors, windows, and other openings. In many cases, they are small enough to pass through screening. Their numbers are incredibly high around sewage plants, where larvae and pupae inhabit the film layer of all the waste. Once inside of a home or building, they reproduce in drains, feeding on scum and other decaying matter. They are attracted to both warmth and light. Bronchial asthma has also been noted in areas with heavy drain fly activity.

Natural Drain Fly Control

Drain flies feed and lay egg casings on the scum build up that accumulates in drains over time. To ensure proper elimination, the drains should be scrubbed with a brush or cleaned using an appropriate drain cleaner. Several drain cleaning products exist that use bacteria to aid in the decomposition of material build-up.

  • Test the drains. Place tape over the drains before going to bed at night. If you have sewage flies, there should be a few stuck to the adhesive in the morning.
  • Look for leaks or stagnant water. Drain flies need moist environments to survive. The presence of drain flies could indicate a faulty air conditioner or broken pipe. Standing water in pots and plants should also be removed.
  • Flush drains with appropriate cleaner. Drains should be scrubbed with a brush and cleaned with drain cleaner. It's illegal to poor pesticides into drains. If you do not have any drain cleaner, you may combine ½ a cup of salt, 1 cup of baking soda, and ½ of a cup of vinegar into the drains. Wait for 20 minutes and run hot water for at least 1 minute. Use a plunger to remove excessive buildup and repeat for any other drains.
  • Garbage disposals and garbage bins should be emptied and cleaned. Drain flies require filth to feed and reproduce. The removal of garbage limits the number of food sources these flies can use.

If you don’t have any vinegar either, consider boiling a pot of water. Pouring it down the drains should be hot enough to destroy any adults and eggs, but it will only loosen the scum buildup inside. To completely get rid of drain flies, the scum has to be removed entirely. Practice of drain sanitation and the correction of any leaks around the home will ensure the timely elimination of drain flies. Sometimes A/C units in attics are equipped with drip pans. In faulty equipment, these pans can overflow, allowing water to leak into wall materials and cause problems with insects and mold. Check crawlspaces for leaky pipes if applicable and correct where necessary.

Professional Drain Fly Control

Pesticide applications are not recommended in drain fly applications. Because most infestations occur directly in the drain, they can easily be controlled by removal of scum build up. If you have positively identified drain flies in the house, it would be in your best interest to find out how close you are to a sewage treatment facility. If you're located within only a few miles of a sewage plant, consider calling the Environmental Protection Agency and filing a complaint. These insects are capable of spreading disease and have caused government concern in the past. The EPA openly serves the public and you can request to send someone out to inspect the property, assisting in the elimination of sewage flies free of charge.