Why do I keep getting drain flies?

Author: Leanne Stokes  |  Last update: Saturday, March 28, 2026

These flies occur naturally in shaded locations containing moist, decaying organic matter, such as wet wooded areas or swamps. They are also commonly associated with: sewage treatment plants and sewer drains. wet compost areas.

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.

Why do drain flies keep coming?

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 find the source of drain flies?

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.

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.

How To Deal With Fruit Flies And Drain Flies

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.

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.

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.

Do drain flies mean a broken pipe?

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.

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.

Can drain flies come out of the toilet?

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 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.

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.

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.

Are drain flies seasonal?

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

How to exterminate drain flies?

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.

Do I need to call a plumber for drain flies?

When To Call In The Professionals. If you have a large number of flies, it may be difficult to get on top of the problem using DIY methods alone. While using enzymatic cleaners and homemade traps can mitigate the problem temporarily, tackling a large clog or infestation is best done by a professional plumber.

Can drain flies make you sick?

Respiratory Problems: Difficulty breathing, wheezing or coughing might also be a sign. This is due to airborne allergens from insects like Drain Flies. Eye and Nose Irritation: Symptoms like a runny nose and watery, itchy eyes are common in case of insect allergies.

Will pouring vinegar down the drain get rid of fruit flies?

Clean the Drain with Vinegar and Baking Soda- This is a natural way clean out the drain and kill off any fruit flies hanging out in there.

Can you use Clorox to get rid of drain flies?

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. The chemical is strong enough to kill the larvae, and the rest of the adult flies should die off within a few hours to a day or so.

How to stop bugs from coming up the drain?

How To Prevent Bugs From Coming Up Your Drains
  1. Decrease Their Food Supply. ...
  2. Install Drain Covers. ...
  3. Use a Mixture of White Vinegar, Baking Soda, and Salt. ...
  4. Get a Professional Drain Cleaning. ...
  5. Fix Leaky Faucets. ...
  6. Replace Shut-Off Valves for Plumbing. ...
  7. Clean Frequently. ...
  8. Contact the Professionals.

Why are the drain flies not going away?

In those instances, their breeding area may be a clogged gutter or other source of standing water outside. What if you're still unable to get rid of drain flies? If you have killed many sets of drain flies over the course of more than 2 weeks, your house many have a well-developed breeding site.

Is bleach or vinegar better for drains?

Drain Line Material

Chlorine bleach can quickly eat away at not only the line but the glue and cement joining the line to the fittings and the condensation pan. If your drain line is PVC, stick to white distilled vinegar for clearing clogs and debris, particularly during winter.

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.

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