For effective drain fly treatment, use three products: Forid Drain Gel Cleaner,
Most exterminators use chemical methods and habitat modification to kill all eggs, larvae, and adult drain flies (removing food sources, etc.).
Drain flies may keep coming back due to poorly executed or ignored mechanical cleaning; failure to eliminate all breeding grounds, surviving eggs, and larvae; and failure to conduct regular cleaning and maintenance of the drain pipes. Adult flies can continue to get in from outside, so seal all possible entry points.
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.
Once you've wiped out their breeding ground, the adults will eventually disappear because there is nowhere left for them to deposit their eggs.
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.
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.
Make a natural cleaning/fly killer mixture.
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.
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).
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.
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.
Pouring boiling water is quite risky as it might lead to a steam burn or scalding. Another thing to keep in mind is what type of material you are pouring in into. If you have a porcelain sink, it is likely to crack due to the heat. All in all, pouring boiling water down your drain will only cause issues down the road.
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.
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?).
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 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.
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.
Your Drain Pipe
As long as standing water is available, they will be able to reproduce. You may notice drain flies after being away for a while, or even after just a few days without using your sink—also watch out for flies regularly in drains that may not get a lot of use, like a guest room or basement.
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 breed in the buildup in pipes. While it is less common for them to appear in a toilet, it could be they are entering the bathroom through a faulty seal between the toilet and sewer flange. This might indicate they are breeding lower down in the pipe and flying upwards.
Drain flies do not come up from your pipes or drains, rather they come from outdoors to the drain when they smell the organic matter they need to breed. Drain Flies get into your home through tiny holes.
When you are using a baking soda and vinegar solution to clean out your drain, you are actually causing the rubber and plastic that are used for the drain's pipes to be eaten away by the mixture. Over time, this rubber and plastic will break down, causing the drain to become even more blocked.
In conclusion, while baking soda and vinegar may seem like a simple and easy solution for cleaning drains, they are not actually very effective in most cases. In some cases, baking soda and vinegar can even cause damage to your pipes.