Flies Running on the Table? Those are Phorid Flies (And it's Bad)
Tiny flies running across your table? They might be Phorid Flies. Learn why they indicate a broken sewer pipe and why pesticides won't stop them.
Most flies fly. It's in the name.
But if you see tiny brown flies that prefer to run across your table in a jerky, erratic pattern—we call it the "scuttle"—you have Phorid Flies.
We also call them "Coffin Flies." You can guess why. They breed in decaying organic matter.
The Sewage Connection
Unlike Fruit Flies (which like old bananas), Phorid Flies love sewage.
If you have these in your house, and you don't have a rotting bag of potatoes anywhere, you likely have a plumbing break under your slab or in the crawlspace.
Moist, organic sludge is leaking into the soil. The flies breed in that sludge and come up through cracks in the floor or drain gaps.
Why Cleaners Don't Work
You can pour bleach down the drain until you are broke. It won't work because the flies aren't in the drain pipe. They are outside the pipe, in the dirt where the pipe is broken.
The Test
This is going to sound weird, but put clear tape over cracks in your floor or around the base of the toilet. If you catch flies coming up from the ground, you need a plumber, not an exterminator. You need to find the break in the line.