Alright, so drain flies are one of those pests that make people feel like something is gross, even when the place is actually pretty clean. You will see these little fuzzy flies hanging out around a sink drain, a floor drain, or a mop sink, and the first instinct is to just kill what you see. And sure, you can swat them, you can spray the air, you can do all that, but that is not going to solve it. Because the adults you see are not the real problem. The real problem is inside the drain.



What happens is this. Over time, drains build up this slimy organic layer on the inside of the pipe. It is basically a mix of grease, soap residue, food particles, and whatever else goes down that drain. That buildup is called biofilm, and it is the perfect breeding zone for drain flies. They lay eggs in it, the larvae feed in it, and then you keep getting new adults coming out. So you might feel like you are losing your mind because you killed ten yesterday, but then today there are ten more. That is why.

And here is another thing people do not always realize. Sometimes the larvae are deeper in the drain, not just right at the opening. So if someone pours something down the drain real quick and thinks it is handled, it might not even touch where the breeding is actually happening. This is especially common in commercial settings, like restaurants or break rooms, because drains get used constantly and buildup happens faster. But it happens in homes too, especially in floor drains and drains that do not get flushed hard very often.

So when we treat drain flies, we do not just treat the air. We treat the source. We use a specialized drain product that is made for drains, and the point of it is to break down the breeding material and disrupt the egg cycle. In other words, we are not just knocking numbers down. We are cutting off the next generation so the problem actually stops. Then the long term solution is pretty simple. Keep drains from building up again. Routine drain cleaning and maintenance keeps that biofilm from coming back, and if the biofilm is not there, the drain flies have nowhere to breed. That is how you keep this from turning into a recurring issue.

Most important takeaways: Drain flies are breeding in the drain biofilm, killing adults does not solve the source, and drain specific treatment plus routine maintenance is what fixes it long term.

Do you have a drain fly or other pest problem in or near Grafton, Saukville, West Bend, Germantown, Sheboygan, or Milwaukee? Call (262)-261-3925