During the day, you'll notice drain flies resting on the wall since they aren't good fliers. 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.
These flies lay their eggs in standing water or in the film that can develop on the inner surfaces of drains. Their larvae feed on the organic matter present in these locations, including decaying vegetation and trapped debris. Drain flies are primarily nocturnal and are most active during the evening.
Look for potential breeding spots near drains or other sources of standing water. If you're unsure which drain is the source, line a clear plastic cup with a very light coating of vegetable oil or petroleum jelly and invert over the suspected drain for several days.
An ongoing or recurring infestation, despite careful sanitation of all drains, can indicate a broken pipe or leak under a slab or in a crawlspace beneath the home.
Pro Tip: Mix eucalyptus oil with water in a spray bottle and use it around drains to deter drain flies effectively.
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.
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, such as kitchen countertops.
Learn the Pest Biology
Knowing the life cycle helps you fight fly infestations. 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.
If your drain fly issue persists, consider using commercial drain cleaners such as Drano. These solutions are formulated to clear out the drains and pipes effectively, removing any debris that might serve as a breeding spot for drain flies. Using these products can aid in preventing new eggs from hatching.
A dried-out p-trap allows for flies to access the drain through rooftop vent traps.
Drain flies are most often the result of a drain or sewer clog, one that limits the flow of wastewater. Unused toilets, refrigerator drains and leaking pipes can also cause them. As we previously mentioned, these insects thrive in stagnant water. What's more stagnant than a backed up drain?
The most glaring problem that drain flies may cause you is a health code violation. Drain flies are not known to cause diseases to humans, but they are known to trigger allergic and asthmatic reactions because of the dust and fragments from their bodies.
Most of the time, flies live in organic materials. Check for flies in places like the soil around houseplants or in your trash. They're also commonly found in bathrooms or in areas around or inside drains. You should also check for gaps along your house's foundation, windows, and doors.
Drain flies feed on filth and scum that can build up in areas such as drains, drain openings, sewers, septic tanks, and kitchen sinks. A great way to identify which drain-source the flies are coming from is to put clear tape over the drain so that they will fly into it and get stuck.
Clean suspected drains with a commercial drain cleaner, and scrub the drain pipe vigorously with a long-handled brush. After their breeding sites have been eliminated, the reproductive cycle is disturbed. If you experience difficulty ridding your home of adult sewer flies, contact your local pest control professional.
Trapped Sewage
Trapped waste that is part of a clog in your drain pipe is also what causes drain flies to infiltrate your home. They love sewage and will look to inhabit and reproduce inside your pipe. This is another reason why it's crucial to deal with clogged drains immediately.
The simple answer is yes but with a caveat. While bleach can kill drain flies and their larvae on contact, it's not the most effective method for long-term control. Bleach's caustic nature allows it to clean the drain pipes and kill some of the larvae.
Boil a pot of water and pour it down the drain where you suspect the drain flies are breeding. Pour a 1/2 cup of baking soda down the drain. Slowly pour a 1/2 cup of vinegar down the drain. Cover the drain with a drain plug, and let it sit for at least 5 to 10 minutes.
Furthermore, there are essential oils that have insect-repellent properties, which can help deter drain flies, including peppermint, eucalyptus, and lavender oils. To use these oils as a deterrent, just dilute a few drops in water and use a spray bottle to wash down the areas that are infested.
HydroScrub® Jetting is one of the most effective professional cleaning services available today. This system uses highly pressurized water—we're talking around 3,500 PSI—to blast all debris within your pipes into the city's main sewer line.
The average cost for drain fly pest control services is $200. However, the price can range from as low as $100 to $500 in some cases, depending on the severity of the infestation and the size of the area that needs to be treated.
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.
Cinnamon – use cinnamon as an air freshner, as flies hate the smell! Lavender, eucalyptus, peppermint and lemongrass essential oils – Not only will spraying these oils around the house create a beautiful aroma, but they will also deter those pesky flies too.
Some soaps with essential oils can repel insects for a short time but, “Irish Spring soap specifically doesn't have enough quantity to register for mosquitoes [and] no ingredients that would repel flies,” he says.
Pine-Sol® is not recommended for use on marble, aluminum, or unsealed, waxed, oiled or visibly worn wood. Q: Where should I NOT use Pine-Sol® Cleaners? A: We do not recommend using Pine-Sol® Original Multi-Surface Cleaner on aluminum, copper or marble surfaces.