Drain flies are small bathroom insects that may point to moisture, dirty drains, or plumbing buildup.

Drain flies are tiny insects that often appear in bathrooms, sinks, and shower areas. Many people think they are regular flies, but they can be a sign of moisture or buildup inside your drains.

These small flies are usually gray or dark brown. Their wings look fuzzy, almost like tiny moth wings. They often stay close to drains, walls, sinks, or damp surfaces.

Drain flies are attracted to wet places with organic buildup. Inside pipes, soap residue, hair, dirt, and body oils can create a sticky layer. This gives the flies a place to lay eggs and multiply.

Using insect spray may kill the flies you see, but it usually does not solve the problem. If the drain is still dirty, the flies can return.

The best solution is to clean the drain deeply. Remove the cover, clear away visible dirt and hair, and scrub inside the pipe with a drain brush. Enzymatic drain cleaners may also help break down buildup.

Keeping the bathroom dry can also make a big difference. Use ventilation, open a window when possible, and wipe wet areas after showering.

A vinegar and dish soap trap may reduce adult flies, but it is only temporary.

If drain flies keep coming back, or if you notice slow drainage or bad smells, it may be time to call a plumber. The issue could be a hidden leak, blockage, or deeper plumbing problem.