I kept noticing tiny, fuzzy flies resting on my bathroom sink and tiles. They barely flew—mostly hopping around—and their strange heart-shaped wings made them look almost harmless. If you’ve seen them too, you’re not alone.
These insects are usually drain flies, also called sink flies or moth flies. They’re tiny, fuzzy bugs that thrive in damp places like bathroom drains, showers, and sinks. Unlike fruit flies or mosquitoes, they aren’t strong fliers and tend to sit quietly on walls or tiles near moisture.
Bathrooms are the perfect breeding ground because drains collect warm, wet organic buildup made of soap scum, hair, skin cells, and grime. Inside the pipes, a slimy layer called biofilm forms, giving drain flies both food and a place to lay eggs.
A female can lay hundreds of eggs in a drain, and within days the larvae hatch and feed on the buildup. That’s why these flies can suddenly seem to appear everywhere at once.
They don’t just breed in obvious places, either. Common hidden spots include:
- Sink and shower drains
- Overflow holes
- Floor drains
- Rarely used pipes
- Damp corners and grout
One easy way to find the source is the tape test: place clear tape sticky-side down over a drain overnight. If flies get trapped by morning, you’ve found a breeding spot.
The best way to get rid of drain flies is by removing the grime they feed on. Regularly scrub drains, flush them with baking soda and vinegar followed by hot water, and keep your bathroom as dry and ventilated as possible.
DIY sprays and bleach may kill adult flies, but they usually don’t solve the real problem inside the pipes. Consistent cleaning is what works best.
With regular maintenance, you’ll usually notice fewer flies within days, though eliminating them can take a couple of weeks. Keeping drains clean and moisture under control is the key to preventing them from coming back.
