How To Give Drain Flies An Eviction Notice

Our Texas insect expert answers common questions about bugs.

By Laura RiceJanuary 29, 2016 9:54 am

Do you have tiny, uninvited guests buzzing around your bathroom? Most people assume they’re gnats – but they might be drain flies. Wizzie Brown, an insect specialist with the Texas A&M Agrilife Extension Office, has the details on these pesky critters and how to give them the boot.

What exactly are drain flies? Are they the same as gnats or moth flies? 

“Drain flies can sometimes be called drain flies, sometimes they’re called moth flies, sometimes homeowners just call them gnats because they’re little tiny flies. They only have two wings but they have these big hairs all over their body and wings – they’re actually very cute. To me. ”

And they actually live in drains? 

“They live in drains, and people don’t realize that they’re there until they have the adults actually flying in the air and then it’s like, ‘What are these coming out of here and why are they coming out of my drain?’ So if you have these little moth looking things, what you can do is put tape over half of the drain and in the morning check it – if you have flies on the tape you know that they’re coming out of that specific drain. What happens is, the larvae live in the slim layer of organic matter that builds up in the inside of drains. It’s not that that’s a bad thing, everybody has it, it’s just a matter of whether you have the flies infesting it.”

How do you get rid of them? 

“All you have to do is take a stiff brush and clean that out and flush it with boiling water. You don’t have to use chemicals down there, you don’t have to pour bleach. You don’t have to pour drain cleaner. Just physically remove the slime and then flush it with boiling water.”

What about other kinds of drains?

“If you have a floor drain, or something like that –  that you can’t actually get a brush in there, they do make a specific bio-gel chemical that you can buy from different pest places. It’s a good idea if you have a drain that isn’t used a lot that you go in there on a somewhat regular basis and flush water down the drain, just to keep it cleaned out.”