During the day, adults rest in shaded areas or on walls near plumbing fixtures and on the sides of showers and tubs. Most activity occurs during the evening when these flies are seen hovering about drains and sinks.
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.
Drain flies also differ in color compared to other small house flies, typically ranging between pale gray to black. While they may look like moths, these little creatures cannot fly very far. You'll notice that they make large hops from place to place instead of buzzing around your home like other pests.
Drain flies, also known as moth flies, sewage flies, and filter flies, like to lay their eggs in wet organic matter. Organic matter can typically be found in clogged and greasy drain pipes in kitchens and bathrooms, storm drains, moist compost, and septic tanks.
Drain flies gather, mate, and lay eggs in moisture or standing water. The slimy film that forms in sewers and drains is a favorite breeding spot. Putting off regular cleaning and maintenance of these areas may attract the pests and offer them a place to feed and develop.
Floor drains often collect standing water in their drain traps, and the stagnant water and sludge in these traps are prime areas for drain flies to lay eggs. Clean floor drains with a stiff brush and hot water, then rinse with a baking soda and vinegar mixture (see above).
Mix together 1/2 cup of salt, 1/2 cup baking soda and 1 cup of vinegar. Pour the mixture down the drain. Let sit overnight, then flush the drain with hot water in the morning. This should kill all flies and the organic material they've been feeding on.
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.
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.”
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.
Lavender, eucalyptus, peppermint, lemongrass, and citronella are just a few of the scents that insects despise (with lavender probably being the most effective). Pouring half or an entire cup of such essential oil onto a sponge or rag, then storing it in a small can, helps keep flies at bay.
Adult drain flies can be found resting on the walls of bathrooms, kitchens, or in basements. They are often seen on inside bathtubs and shower stalls during the day. They become more active at night, hovering over drains, sinks, and other breeding areas.
Drain flies are most commonly found in the bathroom, particularly in drains that have stagnant water or grime sitting in the pipes. Therefore, you'll probably find the small flies in the toilet, sink drain or shower.
Do Drain Flies Die in Winter. Most fly species cannot survive outside temperatures below 32°F (0°C). They die unless they find a warm and conducive place to overwinter, such as your home. Drain flies are one of the few insects that can tolerate cold weather conditions.
Life Cycle: Adult females lay 30–100 eggs in sludge around sewage and drainage areas. Eggs hatch in 32–48 hours, larval stage lasts 8–24 days, pupal stage 20–40 hours. Adults live about two weeks.
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.
Most exterminators use chemical methods and habitat modification to kill all eggs, larvae, and adult drain flies (removing food sources, etc.).
Baking Soda, Boiling Water & Vinegar
The pour half a cup of bicarb soda down the sink as well, followed by a half cup of white vinegar. Let it settle for a few minutes then poor some more boiling water down the drain. Follows these steps every few days until the drain flies have completely disappeared.
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 flies gather, mate, and lay eggs in moisture or standing water. The slimy film that forms in sewers and drains is a favorite breeding spot. Inside structures, they are strongly attracted to light and will be found on glass windows, doors, lamps, and indoor lighting.
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.
These flies will breed in any moist area that they can find. So if you are facing a drain fly infestation that you cannot figure it out, you may want to look deeper for the cause. The problem could be from a leaking pipe or drain under the sink or even a leaking pipe inside of your walls.
Mix 1/2 cup salt, 1/2 cup baking soda and 1 cup of vinegar and then pour the mixture down the drain, leaving it overnight. In the morning, pour boiling hot water down the drain.
For the most part, drain flies are not dangerous and not harmful. Having drain flies around your home does not mean your drains are dirty or your kitchen, bathroom or other areas are unclean. They are opportunistic insects and can get inside and find any moist area to lay their eggs and breed.