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What Are Drain Flies And Why Do I Have Them?

drain flies
Reading Time: 3 minutes

If you have areas around your home that are humid with a build-up of organic waste, you’re probably battling drain flies. As their name suggests, these pesky critters are often found around drains in your home. Some people refer to them as moth flies, as their broad wings, covered in fine hairs, resemble those of a moth. Before you panic, drain flies are not immediately dangerous. If they are left to breed in abundance, you could have a health issue around your home that needs attention.

What Are Drain Flies?

Diptera is the fly order name in which drain flies are classed. This Latin word means that they have two wings. House flies and bottle flies also have 2 wings but they are not the same. The flies belong to the family Psychodidae and are also known by some of these common names:

  • Sink flies
  • Sewer flies
  • Sewer gnats
  • Filter flies

What Do They Look Like?

Drain flies are very small flies and are similar in size to fruit flies. They are much smaller than house flies. They range in color from a light gray-brown all the way to a much darker blackish-brown. They have short, fat bodies and are not agile and speedy fliers like their house fly cousins. When they do fly, you may notice that they do not fly over long distances, preferring to rather move from one place to another when disturbed. They have a furry look to them due to the fine hairs that cover their wings and bodies.

Where Do They Live?

As mentioned previously drain flies are often seen around the drains in your home. Both outside and indoor drains are areas where the flies will lay their eggs. They seek out areas where there is stagnant water and decaying organic matter.

They lay their eggs in the film that collects on the inside of drain pipes and sewers. An adult drain fly can lay anything from 30 – 150 eggs. Once the larvae hatch, they feast on the organic matter in the stagnant environment. The pupal stage lasts just short of 2 days, after which, an adult drain fly emerges.

But Why Do I Have Drain Flies?

Probably because you’re overdue on some drain maintenance. In South Florida, humidity is always an issue. The humid weather means that standing water never really dries up. If any organic matter falls into the water, it will begin to stagnate and decay. This is an ideal nursery for drain flies.

It’s not always a drain though as these annoying pests have even been known to breed in the puddles created by air conditioning units. Let’s have a look at some of the more common areas where they tend to infest.

Kitchen Sinks

After the dishes have been washed there is always some food left on the plates. When the sink is drained this food collects on the inside of the drain pipes. If they are not cleaned regularly by an experienced drain cleaner, the flies will make it their home.

Bathroom Drains

Shower and bath drains, as well as bathroom sinks, can all collect organic matter with regular use. Dead skin cells and hair form “Petri dishes” for bacteria to proliferate in. These bacterial colonies are irresistible to the filter flies and they will find it and begin to lay eggs.

Outdoor Sewers

Any exposed outdoor sewers will also attract flies. Areas, where there are exposed grates, give them easy access to the drains. Raw sewage is a welcome food source for winged pests.

Drain Cleaning Professionals In Broward County

If you are battling a drain fly infestation and need a licensed professional, give Art Rooter, Sewer & Drain Cleaning a call. We have offices in Broward County and have been serving South Floridians for over 30 years. Give us a call at 1-833-470-2880 or contact us on social media.


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