How to Get Rid of Drain Flies April 10, 2025

If you’ve noticed small, fuzzy bugs hovering near your bathroom or kitchen sink, there’s a good chance you’re dealing with drain flies. While they’re not dangerous, they’re unsanitary — and frustrating to get rid of if you don’t address the root cause.

Here’s what to know about where they come from, how to eliminate them, and how to prevent them from coming back.

What Are Drain Flies and Why Are They in My House?

Drain flies, sometimes called sewer flies, filter flies, or sink gnats, are tiny, moth-like insects that thrive in moist, organic matter. That makes your drain lines, especially those that haven’t been cleaned in a while, the perfect environment for them to breed.

They’re most commonly found in:

Bathroom and kitchen sink drains
Shower or tub drains
Floor drains in laundry rooms or basements

You may also notice a musty smell or see them flying in small circles near your drain. They don’t bite, but they multiply quickly and can signal a bigger drainage issue.

What Causes Drain Flies to Show Up?

The main cause is a buildup of organic debris inside your drains—things like hair, soap scum, grease, and food particles. These materials create a layer of sludge where drain flies lay their eggs and feed.

Common reasons they show up include:

Rarely used drains that retain stagnant water
Partially clogged drains that trap debris
Leaky or slow-moving pipes that collect moisture behind walls or under floors

How to Get Rid of Drain Flies

If you’ve spotted drain flies in your home, your first step is to clean the area where they’re breeding—your drains.

Here are a few methods that can help:

1. Boiling Water Flush

Pour a pot of boiling water down the affected drain once or twice a day for a few days. This can help dislodge and kill early-stage larvae.

2. Enzymatic Drain Cleaners

Choose a natural, enzyme-based cleaner that breaks down the organic matter in your drain. Avoid harsh chemical cleaners, which can damage pipes without solving the underlying issue.

3. Drain Scrubbing

If you can, remove the drain cover and use a pipe brush or plumbing snake to physically scrub the inside of the drain where debris collects. This is often the most effective way to remove the buildup that allows drain flies to thrive.

4. DIY Trap (Optional)

While not a long-term solution, you can set a shallow dish of apple cider vinegar with a drop of dish soap near the drain to catch adult flies while you work on eliminating the source.

Still Seeing Flies? It Might Be Time to Call a Plumber

If drain flies keep coming back after you’ve tried cleaning, you may be dealing with:

A deeper blockage in your drain or sewer line
Leaking or broken pipes in your wall or under the slab
Multiple breeding sources across your plumbing system

A professional plumber can perform a camera inspection to identify the issue and recommend a deeper cleaning method like hydro jetting, which uses high-pressure water to remove buildup throughout your pipes.

Schedule a drain cleaning with WeCo Rooter if you need help removing stubborn buildup and restoring full flow.

How to Prevent Drain Flies From Returning

Once the infestation is gone, regular drain maintenance can keep them from coming back.

Here’s how to keep your drains clean and fly-free:

Run water through rarely used drains weekly
Avoid putting grease, hair, or food scraps down drains
Use enzyme drain cleaner monthly as a preventative
Clean visible drain covers and strainers regularly
Schedule professional drain cleaning once a year if buildup is common in your home

Final Thoughts: Don’t Ignore Drain Flies

Drain flies might seem like a minor annoyance, but they’re often a sign of something building up inside your plumbing system. Addressing them quickly can prevent more serious clogs and hygiene concerns.

If you’re seeing signs of drain fly activity and home remedies haven’t helped, WeCo Rooter is here to help. Our team can assess your drains, clear any buildup, and help you get back to clean, fully functional plumbing.

Still seeing drain flies no matter what you try? Book a professional drain cleaning today!