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How to Deal With Drain Flies in Your Plumbing


Have you noticed small moth-like flies sitting on your bathroom walls? If they are black or brown, look fuzzy and have wings shaped like that of a moth, you are probably looking at a drain fly. Drain flies reproduce and mature in drains, sump pits, under slab floors and in other wet and dark areas that contain organic matter. If you have been slacking on your Maryland plumbing maintenance, it’s possible that the drain flies took advantage of it.

To know for sure, place a piece of tape over a drain or other opening you suspect the flies use as a nest, puncture a few holes and leave overnight. If it’s drain flies, you will see flies stuck to the tape in the morning.

Why Do I Have Drain Flies?

One drain fly can lay between 30 and 100 eggs, so it takes just two flies to cause a problem in your bathroom or kitchen. Here are some of the reasons why the drain flies have decided to make your home their home:

  • You have dirty drains packed with decomposing organic matter. It probably sounds more gross than it actually is, and by “decomposing organic matter” we mean food debris or skin oils accumulated as a film inside your drains.
  • Organic matter is also contained in sewage, so the presence of drain flies may indicate a sewer leak.
  • If you see drain flies coming from under the slab, you might have a broken drain pipe.
  • A contaminated sump pit may also be to blame here, even if the flies are not seen anywhere near it.

How to Get Rid of Drain Flies

Drain flies are fairly calm insects that are harmless to humans. They are not very good at flying, so they mostly sit on the walls, counter tops, sinks and other areas close to their breeding grounds. However, that decomposing organic matter they come in contact with may contain bacteria that these flies may spread around your home. So even if you don’t mind drain flies, it’s a good idea to get rid of them by fixing the underlying problem.

Let a professional Carroll County plumber inspect your drains and plumbing to determine whether there is a leak or a broken pipe that is attracting the flies. If so, it will need to be uncovered and fixed. Sometimes, the problem is as simple as a dirty drain, in which case it should be thoroughly cleaned with a proper disinfecting agent.

Keeping the drain flies in check is as easy as maintaining your drains and the rest of the plumbing free of debris and damage. Give Michael Runk Plumbing and Heating a call or schedule an appointment online if you need help with plumbing maintenance.

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