Home Openings. Since they are so small, they can often make it through doors, windows, and other openings around your home. They're looking for standing water, similar to other flies and insects.
Drain flies thrive in stagnant and standing water. Common sources include slow or clogged drains, rarely used and unused toilets, refrigerator drain pans, and standing water created by leaking pipes. They typically enter buildings through basements, windows, and drains.
Put Screens On Your Windows and Doors
If you do not already have screens on your doors and windows, this should be a top priority! Screens help prevent flies and other insects from getting in your house when the doors and windows are open.
Drain flies are attracted to small amounts of stagnant water they find in plumbing pipes, sinks or other drainage areas. The flies feed on tiny amounts of bacteria, algae and sewage, so you can find them gathering around kitchen and outdoor sinks, shower and bathtub drains, basement sinks, sewers and septic tanks.
If you notice a big amount of drain flies in your home then you likely have issues with poor sewage drainage or overflows, which make a happy breeding ground for these pests. Make sure to contact a pest control professional to handle a potential infestation.
Essential oils are sometimes used to keep flies away from infested sections and also to kill them. Lavender, eucalyptus, peppermint, lemongrass, and citronella are just a few of the scents that insects despise (with lavender probably being the most effective).
The larval stage of drain flies lasts up to 24 days, while the pupal stage lasts between 1 and 2 days at most. The larvae feed on bacteria, fungi, and other microorganisms that develop in the breeding medium in drains, standing water, and even sewage treatment beds.
A cup of household bleach is generally more than sufficient to kill most drain flies, and all you need to do is pour it down the affected drain.
Adult drain flies usually live about two weeks, but newly emerged adults rapidly replace them. These flies are also known as moth flies due to their appearance: they are small and furry with large, ovoid wings and prominent antennae.
House Flies may be found feeding and breeding in fresh manure, rotting fruits and vegetables, garbage, damp garbage, and decaying organic materials that are located outside of the structure. Most of the time, when you find house flies inside, it is because they are coming inside the structures.
One possible sign of an undetected mold problem in your home or office could be the presence of Phorid flies, sewer flies or some other gnats or bugs.
Drain flies are typically only found in the summertime or in places with moderate year-round climates. Cold weather kills off more drain flies than any of their predators. If drain flies are able to find a home indoors, they can continue their development throughout the year, even during the winter.
Most exterminators use chemical methods and habitat modification to kill all eggs, larvae, and adult drain flies (removing food sources, etc.).
For effective drain fly treatment, use three products: Forid Drain Gel Cleaner, Gentrol IGR Aerosol, and Pyrid. Forid is an organic microbial grease degrader that breaks down organic material and waste, which will eliminate their food sources and their breeding grounds.
They do not bite, sting, or spread diseases, but their decaying bodies may cause allergic reactions. They can also spread bacteria from trash, decaying vegetables and fruits. Drain flies breed in areas that are moist and have a lot of organic remains, including: Sinks.
Preventative Maintenance
Pouring bleach into the drain when the unit is not operating can leave residual bleach, which will damage the drain pan and line. Using vinegar for preventative maintenance throughout the year will keep your drain clean and clear and will not damage your line.
Once you've wiped out their breeding ground, the adults will eventually disappear because there is nowhere left for them to deposit their eggs.
Drain fly problems can go away on their own—but only if the insects find the environment inhospitable. Those with a minor infestation can simply flush their toilets and run their faucets more frequently to flush out the flies and larvae. Others will have to deep clean their drains and set up traps.
Adult flies emerge from the breeding sites but may remain nearby. Drain fly control often fails because people don't realize just how resistant the scum and the larvae are to boiling water, bleach, detergent, and even caustic drain cleaners (see How Can I Get Rid of Drain Flies?).
Create a fly and wasp repellent.
This DIY pest repellant should be a staple in the Southern home. Pour equal parts water and Pine-Sol in a spray bottle to spritz on outdoor furniture, the deck, and indoor areas where flies are most likely to flock to, such as kitchen countertops.
The vinegar's smell will attract the drain flies, and the wrap will trap them inside the bowl. Another option is to mix a few drops of dish soap with a cup of vinegar. The vinegar attracts the flies, and the dish soap makes it impossible for them to stand on the surface, so they drown.
Your kitchen sink and garbage disposal is paradise for drain flies. Their ideal breeding environment is wet, humid, and laced with food waste to feed on. Your first course of action to deal with drain flies is prevention. Don't throw anything down your garbage disposal that will cause build-up.