Do drain flies fly all over the house?

Author: Sabina Kirlin  |  Last update: Wednesday, February 25, 2026

Once they get inside, drain flies are typically found flying or crawling around kitchens, bathrooms, laundry rooms, as well as damp basements or crawl spaces. When outdoors, drains flies are attracted to properties with piles of compost or wet organic debris like leaves, grass, and fallen or decaying trees.

Can drain flies be all over the house?

Since they are so small, they can often make it through doors, windows, and other openings around your home. They're looking for standing water, similar to other flies and insects.

How to find out where drain flies are coming from?

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. This will help catch emerging adults and identify breeding sites.

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.

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

How do I permanently get rid of 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.

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.

Why do I suddenly have drain flies?

Drain flies are most often the result of a clog in a drain or sewer line, it doesn't matter if it's buildup, a soft clog or a hard clog – it just needs to limit the flow of wastewater, causing it to become stagnant and a breeding ground for bacteria.

What temperature kills drain flies?

While this won't kill adult drain flies that have the biological defenses to withstand it, boiling water will kill larvae and eggs. Use a mixture of equal parts salt, baking soda, and vinegar, and pour it down your drain. The mixture may fizzle and foam, but it can also help clear out your drains.

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.

Where do drain flies go at night?

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. You'll most likely see only a few at a time, as you only rarely see drain flies in large numbers at once.

How to figure out where flies are coming from?

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.

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.

How to find a drain fly nest?

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.

Do I need a plumber to get rid of drain flies?

Pest Control

The goal is to eliminate their breeding site. The most effective method for doing this is to call a plumber and have them mechanically clean the pipes of the slime and organic material that tends to collect in the pipes and drains.

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 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.

Will 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.

Can I pour bleach down the sink to get rid of smell?

Bleach is highly effective in killing bacteria and other microbes causing the foul smell. However, it should be used sparingly to avoid damage to your plumbing system.

Can drain flies come out of the toilet?

The tiny flies you see in your toilet are called Drain Flies. Also known as sewer gnats or moth flies, they can be a frustrating and unsightly nuisance in your home. These tiny insects are a common sight in Singapore homes, as they thrive in the moist and organic matter found in drains, pipes, and sewage systems.

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 to get rid of drain flies fast?

To get rid of drain flies, clean the drains where they lay eggs. Pour a mix of hot water, baking soda, and vinegar down the drain to break up the gunk they live in. I did this once, and it worked like magic! You can also cover the drain overnight with tape to see where they're coming from.

What is the best cleaner to get rid of drain flies?

Vinegar and baking soda: Pour 1/2 cup baking soda and 1 cup of vinegar down the drain.

Where do little black flies in the bathroom come from?

Clogged or Dirty Drains: Organic debris that builds up in your plumbing provides an ideal breeding ground for drain flies. Regular cleaning of your drains and routine pest control treatment helps prevent these pests from taking hold.

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