Fruit Flies Vs Drain Flies [7 Ways to Identify Them]

You can tell drain flies and fruit flies apart because drain flies have dark wings and are covered in fine hairs like a moth. Fruit flies have transparent wings, red eyes, and do not have moth-like hairs. The yellow-brown color of a fruit fly’s body is different from the drain fly’s gray, brown, and black coloration. Drain flies prefer to breed in bacteria, sewage, and other slimes that can build up in drainage pipes. Fruit flies lay their eggs on spoiled food like fruits and vegetables. In some cases, fruit flies will lay eggs in your drain if enough food residue has built up in your plumbing or disposal.

Fruit Flies vs Drain Flies

What Flies Live in Drains?

The two most common flying insects you will find living in your drain and flying around it are drain flies and phorid flies. Fruit flies are similar in size and shape to these other species, but they are less likely to reproduce in your plumbing.

  • Drain flies lay their eggs in drain pipes so their larvae can feed off the buildup inside.
  • Phorid flies create colonies and reproduce in drains, then swarm around them.
  • Fruit flies can also appear near sinks, especially in the kitchen.
  • Fruit flies are less likely to reproduce in drains, but it is possible for them to do so.

Flies that inhabit drains tend to be very small but can multiply rapidly, infesting a restroom or kitchen if the conditions are right. Correctly identifying which species is invading your home helps you take the best measures to stop the infestation. Because they lay their eggs in drains, you can use these tips to eliminate drain flies. However, those tactics won’t work for fruit flies, since they typically lay their eggs in fruit or vegetables.

7 Differences Between Fruit Flies and Drain Flies

Fruit Flies vs Drain Flies infographic

Both fruit flies and drain flies are notorious household pests. These insects are fairly different in how they look and behave. Once you know the difference, you will be able to identify which fly is buzzing around your drain. Just look for these signs:


Although drain flies and fruit flies are both small, they still have distinctive coloration that can be used to tell these insects apart. Fruit flies have yellow-brown bodies and often have red eyes. Drain flies are darker, often in shades of brown, gray, and black. It is almost impossible to see the eyes of a drain fly, so the presence of red or orange eyes means you have found a fruit fly.

Wing Shape

To tell drain flies apart from fruit flies, look at the wings. Drain flies hold their large wings flat when they rest on a surface, giving them a triangular shape similar to a moth. A fruit fly’s wings are much smaller and harder to see from a distance. They are transparent and held straight behind them when the fruit fly is at rest or crawling. Distinctive wings mean you are looking at a drain fly, while hard-to-see wings indicate a fruit fly.

Fur and Antennae

Drain flies have a furry appearance that has earned them the nickname “moth fly.” Fruit flies do not have a furry appearance. A drain fly’s head is covered in fuzz, and they grow two fuzzy antennas that spread out from the sides of the head. So, if you see a pair of long antennae, you can be confident that you’ve spotted a drain fly.


Drain flies are almost twice the size of fruit flies, which can make them easier to identify. Drain flies can grow up to 5 millimeters in length. For comparison, 5 millimeters is about the width of the eraser on a pencil. Meanwhile, fruit flies are 2–3 millimeters in length. This is about the width of the tip of a crayon. Very small, hard-to-see flies are typically fruit flies.

Activity Level

Drain flies are usually spotted sitting unmoving near a drain. They are poor fliers that prefer to crawl. In comparison, fruit flies are typically seen being active outside of drains. You might see fruit flies hovering around, performing mating dances, or even fighting each other. Drain flies, on the other hand, will turn a drain into their breeding ground so you won’t necessarily see them being very active outside of it.

Reaction to Water

Running the faucet over a drain you suspect to have flies in it can help you identify them. A fruit fly hanging around the tap is likely to be washed away with running water or be drowned. Drain flies are more likely to take flight even when you get them wet. This is because drain flies have adapted microscopic scales that keep their wings from getting wet. This allows them to fly even if you splash them with water.

Breeding Ground

Fruit flies are attracted to overripe fruit and other organic material for feeding and laying their eggs. So, you’ll commonly find them on food you leave out in the open. Drain flies, on the other hand, breed in stagnant pools of water. Bacterial buildup grows inside your drain when your sink or tub isn’t draining properly. This attracts drain flies, since they lay their eggs in this buildup. So, you’re less likely to find drain flies on your food than fruit flies. However, if your sink drain is infested with drain flies, you can use Drano to kill them.

What Flies Lay Their Eggs in Your Drain?

Drain flies commonly lay their eggs in drains, and their larvae live inside your drain until they grow to adulthood. The bacteria inside a slow-draining sink or shower drain is the main food source for drain fly larvae. Fruit flies prefer to lay their eggs in overripe fruit or in garbage cans.

  • A drain fly will lay 30-100 eggs in drains with bacterial build-up and stagnant water.
  • A fruit fly will lay up to 500 eggs on the surface of rotting food.
  • Drain flies take around 4 weeks to mature from egg to adult.
  • Fruit flies take around 10 days to develop into mature adults once they hatch.

The eggs of both fruit flies and drain flies hatch in a little over a day. However, one fruit fly can lay far more eggs than one drain fly. Also, because fruit flies mature faster, they multiply and become a big problem faster than drain flies.

Do Fruit Flies Lay Eggs in Drains?

In order for fruit flies to lay eggs in your drains, there must be food matter in them. They are called fruit flies because they typically lay their eggs in fruit. If there is no fruit around, then other decomposing foods and organic matter make a great place for fruit flies to breed.

  • The kitchen sink, garbage disposal, and even dishwasher can all be targeted by fruit flies if they are dirty with food waste.
  • You are unlikely to find fruit flies in bathroom drains, unless you bring food or drink in there.
  • Keeping drains and waste bins free of rotting food will reduce the likelihood of fruit flies infesting your home.
  • If you suddenly have fruit flies, it is likely that they came into your home as eggs on fruit from the grocery store.

If there isn’t any lingering food in your drains, fruit flies will have no interest in them. Regular maintenance and cleaning of garbage disposals and kitchen sinks can help prevent flies of any kind from breeding there.

How to Tell the Difference Between a Drain Fly and a Fruit Fly

Both fruit flies and drain flies can potentially take up residence in and around your drains. Here’s how to tell them apart:

  • Fruit flies are yellow-brown in color.
  • Drain flies are dark brown or gray.
  • Most fruit flies have red eyes.
  • Drain flies do not have visible eyes.
  • Fruit flies have transparent wings and no visible antennae.
  • Drain flies look like tiny moths with feathery antennae and broad, furry wings.
  • A drain fly is slightly larger than a fruit fly.
  • Fruit flies are active fliers.
  • Drain flies are weak fliers that prefer to crawl.
  • Fruit flies prefer to congregate on food, especially fruits and vegetables.
  • Drain flies live and breed in and around drains, not food.
  • Fruit flies breed and mature faster than drain flies, making them a more difficult pest to eliminate.
  • Fruit flies can congregate in drains if they have food waste in or around them.

You are most likely to see drain flies in bathrooms and basements, especially if there is standing water in any of the plumbing. Fruit flies can be found wherever food is and they often enter a home via fruits or vegetables you bring home, rather than from your drains.

Locust vs Grasshopper

Locusts Vs Grasshoppers [4 Key Differences]

Does vinegar kill caterpillars?

Does Vinegar Kill Caterpillars? [4 Reasons to Avoid Vinegar]