What draws drain flies?

Author: Michele Kassulke  |  Last update: Tuesday, June 2, 2026

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.

Why am I suddenly getting 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.

How do I permanently get rid of drain flies?

Apple cider vinegar with a drop of dish soap: leave in a shallow plate or bowl (I used a tiny fish bowl from thrift store) near drains to catch those flying around. They will fly in and drown. Replace every day or every other day as needed.

How to find out where drain flies are coming from?

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.

What attracts drain flies?

Your Drain Pipe

The flies are attracted to the water and bacteria buildup and set up camp there. As long as standing water is available, they will be able to reproduce.

Do this and you will never see flies and mosquitoes in your house again

What smell do drain flies hate?

Peppermint, eucalyptus, and tea tree oils are especially beneficial. Pour a few drops of the chosen oil with water down the toilet. The oils' pungent aroma repels drain flies and disturbs their breeding cycle. To keep the solution effective, reapply it every few days.

How long does a drain fly infestation last?

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.

Do drain flies always mean a leak?

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.

Does Drano get rid of drain flies?

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.

Are drain flies a health code violation?

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.

Can you pour boiling water down the drain?

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 is the best drain fly killer?

Most Effective Products
  • Aerosol. Pyrid Insecticide Aerosol. 18 Ounce Can. As low as $27.99.
  • Ready-To-Use. Forid Drain Gel Cleaner. 64 Ounce. As low as $65.44.
  • Aerosol. Gentrol Aerosol Insect Growth Regulator. 16 Ounce. As low as $17.45.

Are drain flies seasonal?

Drain Flies are seasonal and you'll notice them in the spring... or not! Biochem Environmental Solutions Inc.

How do you get rid of drain flies in 5 minutes?

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.

Will bleach get rid of drain flies?

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.

Do drain flies mean a broken pipe?

Phorid flies are also known as sewer flies. This may be a good name for them, since they are often associated with damage to sewer lines that are in or close to the house or building. These flies are often associated with clogged drains inside buildings.

How do plumbers get rid of drain flies?

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.

What scent gets rid of drain flies?

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.

What causes an infestation of drain flies?

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.

Do drain flies eventually go away?

Another clue that the bug you're looking at is a drain fly is that it's bad at flying. They won't go more than a few feet, and it might seem as though they're hopping rather than flying. They also don't bite. Nine times out of ten, a drain fly problem will go away on its own.

What's the difference between drain flies and sewer flies?

Drain flies, also known as moth flies or sewer flies, are small, hairy, moth-like insects measuring 2 to 5 millimetres long depending on the species. They are weak fliers and are often seen walking near breeding sites. Females lay 30 to 100 eggs in masses on the surface of breeding medium.

Do drain flies mean mold?

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.

Do drain flies come out more at night?

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.

Does blue light attract drain flies?

A blue light/UV trap can help lure and trap drain flies.

What temperature water kills drain flies?

The process of getting rid of drain flies is generally pretty simple. Usually, boiling water or baking soda and vinegar are enough to flush out their nest and send them on their way.

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