One of the reasons that these types of critters — drain flies, in particular — are so difficult to get rid of is that they have water-repellant hair all over their bodies. Furthermore, the drain fly larvae are difficult to drown since “they are able to trap air bubbles and remain submerged for a day or more.”
The best way to get rid of drain flies is by eliminating their breeding grounds. Get rid of organic matter in your drains using DIY homemade solutions or store-bought products.
What Causes Drain Flies? 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.
Most exterminators use chemical methods and habitat modification to kill all eggs, larvae, and adult drain flies (removing food sources, etc.).
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.
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.
Don't stop looking when one breeding source has been found. In most cases, several breeding sources will be present. Drain flies, or moth flies, can be found in moist, highly organic debris areas such as sink drains, moist mops, sewage treatment facilities, storm drains, dung, and rotten vegetation.
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.
Nine times out of ten, a drain fly problem will go away on its own. Once you get rid of the drain flies that you see, start flushing toilets and running the water in your sinks. This eliminates the standing water in which they dwell.
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.
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.
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.
Some species hold the wings out to the side, which gives them a moth-like appearance—hence the name "moth fly." They are weak fliers and make irregular, hesitating flights covering only a few feet in short, jerky lines. Eggs are tiny, brown or cream-colored and are laid in irregular masses of 10 to 200.
At night, when they are active, they will congregate towards light sources, like lampshades. They will also feed and breed at night, so you'll see them near food sources or breeding areas. You'll most likely see only a few at a time, as you only rarely see drain flies in large numbers at once.
To make an all-natural drain fly trap, fill a bowl with apple cider vinegar and cover it with plastic wrap. Punch small holes in the wrapping. 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.
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.
Behavior: Drain flies are most active at night. They are weak flyers that make short hopping flights of a few feet when they are disturbed. Drain flies rest on surfaces with their wings held over their back like a roof. You'll usually find a drain fly close to its breeding ground.
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.
If temperatures fall below freezing, and drain flies don't find a warm place to overwinter, they will die. But, drain worms (the larvae) can still survive by staying below the gelatinous film in drains. They will thrive all year round if the cold temperatures don't reach them.
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.
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.
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.