---
title: "How to Get Rid of Drain Flies"
description: "Tiny winged insects flying out of sinks are the stuff of nightmares. Why do you have drain flies, and how can you get rid of them? Here's what to know."
date: "2015-07-07"
modified: "2026-07-16"
authors:
  - name: "BobVila.com Staff"
    link: "https://www.bobvila.com/authors/bob-vila-staff/"
url: "https://www.bobvila.com/articles/how-to-get-rid-of-drain-flies/"
categories:
  - "DIY"
  - "Interior"
  - "Pest Control"
  - "Pests"
tags:
  - "How To"
  - "News"
---

# How to Get Rid of Drain Flies

![A drain fly (Psychodidae) hanging around in the bathroom close to a sink.](<https://www.bobvila.com/wp-content/uploads/2015/07/drain-fly-sink.jpg>)
*Photo: Birgit Bierschenk via Adobe Stock*

Drain flies, also known as moth flies, live and breed inside your plumbing pipes, feeding on decomposing material and laying eggs within the gelatinous slime that collects along the walls of your drain. According to Rich Mullins, an Indiana-based plumber with over 25 years of plumbing experience and founder of [H20 Plumbing](<https://myh2oplumbing.com/>), “a clogged or slow-moving drain creates a perfect breeding ground for these pests and identifying an infestation can be tricky.”

While these insects don’t bite or spread disease, no one likes to see tiny winged bugs flying out of otherwise clean sinks. If you see drain flies in your bathroom, follow these steps to identify the source of drain flies and the best drain fly killers to eliminate them.

## What are drain flies?

Drain flies (*Psychodida*e*)* are tiny insects commonly found in damp areas like drains and in standing water (think unused toilets and sewage systems). These mothlike pests are small, measuring roughly ⅛-inch long, and feature a brown, black, or gray exoskeleton covered in fuzzy hairs. They thrive in moist environments and often lay their eggs in the debris that builds up inside drains. Drain fly larvae, known as maggots, can also develop in water. The larvae are often overlooked, however, because they are so small.

The life cycle of a drain fly can last anywhere from 8 to 24 days, depending on the temperature of the drain and the surrounding climate. Drain flies don't bite nor are they dangerous to humans, but they can become a nuisance once they invade a home or commercial space.

"I advise using a simple test: place a piece of tape over the drain at night. If you find flies stuck to the tape in the morning, it's a clear sign of an infestation.”

—Rich Mullins, founder of Indiana-based [H20 Plumbing](<https://myh2oplumbing.com/about/>)

## Drain flies vs. fruit flies: What’s the difference?

![Moth Fly (Left) Vs Fruit Fly (Right)](<https://www.bobvila.com/wp-content/uploads/2015/07/Bob-Vila-Slides-Horizontal-2023-10-18T170912.018.jpg>)
*Photos: iStock and BobVila.com*

Drain flies and [fruit flies](<https://www.bobvila.com/articles/how-to-get-rid-of-fruit-flies/>) are often mistaken for each other, as they’re both small in size and similar in appearance. They do, however, have distinct differences.

**Similarities:**

- They have small bodies.
- They breed in standing water, drains, and garbage disposals.

**Differences:**

- Drain flies thrive in moist environments like drains and sewage systems; fruit flies are attracted to ripe fruits and vegetables.
- Drain flies primarily feed on debris and sludge-like substances; fruit flies are attracted to fruit and sugar.
- Drain flies have a fuzzy, moth-like appearance; fruit flies have a rounded, slender silhouette with clear wings.

### Tools & Materials

Bobvila.com may earn a commission from purchases made through these links.

- [Drain snake](<https://www.amazon.com/36-Snake-Drain-Clog-Remover/dp/B01LM2L50I/?tag=bv-how-to-get-rid-of-drain-flies-20>)
- [Plunger](<https://www.amazon.com/dp/B00P7VW2H6/?tag=bv-how-to-get-rid-of-drain-flies-20>)
- [Large bowl](<https://www.amazon.com/Tovolo-Stainless-Steel-Mixing-Quart/dp/B001C0B02E/?tag=bv-how-to-get-rid-of-drain-flies-20>)
- [Pipe brush](<https://www.amazon.com/dp/B01N6QEINN/?tag=bv-how-to-get-rid-of-drain-flies-20>)

- [Baking soda](<https://www.amazon.com/Arm-Hammer-Pure-Baking-Ounce/dp/B00K1JFC0S/?tag=bv-how-to-get-rid-of-drain-flies-20>)
- [Masking tape](<https://www.amazon.com/dp/B00004Z49T/?tag=bv-how-to-get-rid-of-drain-flies-20>)
- [Enzyme drain cleaner](<https://www.amazon.com/dp/B079K94HHV/?tag=bv-how-to-get-rid-of-drain-flies-20>)
- [Vinegar](<https://www.amazon.com/Amazon-Brand-Happy-Distilled-Vinegar/dp/B08P5569PX/?tag=bv-how-to-get-rid-of-drain-flies-20>)

## Project Overview

***Working time****: 20 minutes*
***Total time****: 20 minutes*
***Skill level****: Beginner*
***Estimated cost****: $15 to $30, depending on supplies already on hand*

## Before You Begin

While bleach will kill drain flies, it can also damage household drains and septic systems. The chlorine in bleach can even corrode the metal components in water tanks and potentially lead to contamination of the water supply. Skip the bleach and instead read on for safer methods of killing drain flies.

## How to Get Rid of Drain Flies

### Step 1: Identify the affected drains.

![The kitchen sink is clogged and the water does not run down the drain. The plumber has to come](<https://www.bobvila.com/wp-content/uploads/2015/07/iStock-1350035696.jpg>)
*Photo: iStock*

Before you can rid your home of drain flies, you need to identify the affected drains. Adult drain flies love to feed and breed in slow-moving or clogged drains, because they provide plenty of decomposing material where the insects can complete their life cycle. If any of your drains are backed up, chances are that those are the root of the problem.

To determine whether you have a drain fly infestation, Mullins says “homeowners might notice these small, flying insects near drains, especially during the evening or at night. To confirm the issue, I advise using a simple test: place a piece of tape over the drain at night. If you find flies stuck to the tape in the morning, it's a clear sign of an infestation.”

You don’t want to block airflow in the drain, so just make an “X” in the tape over each drain opening.

- Put the tape on the drains before you go to bed and leave it there overnight to catch any insects that may try to fly out. (Drain flies are most active at night.)
- Check the tape the next morning for signs of bugs to determine which drains are the sources of your fly problem.

### Step 2: Use a drain snake to clean the affected drains.

![Woman wearing goggles and gloves twists a drain auger in a bathtub drain.](<https://www.bobvila.com/wp-content/uploads/2016/01/how-to-use-a-drain-snake_turn_auger.jpg>)
*Photo: Tom Fenenga for BobVila.com*

Once you’ve identified the problem drains, you need to eliminate the flies’ breeding zones by cleaning them. Resist the urge to pour a bottle of chemical drain cleaner down the drains. Doing this won’t effectively eliminate the decomposing material in your pipes and traps, and it’s not good for your pipes.

Instead, start by running warm water down the drain. Next, insert a [drain snake](<https://www.bobvila.com/articles/best-drain-snakes/>) or pipe brush and use a gentle up and down motion to remove the built-up slime covering the inside of the drain pipe. A [plunger](<https://www.bobvila.com/articles/how-to-use-a-plunger/>) can also be used to help pull out any leftover material from the pipes. Mullins also recommends another solution that can help rid your drain of flies. “Remove any hair, debris, or gunk that might serve as a breeding ground,” Mullins states. “Pouring a mixture of vinegar and baking soda down the drain can help break down organic matter and eliminate breeding sites.”

### Step 3: Clear the U-trap.

![Person wearing rubber gloves touches a P-trap under the bathroom sink.](<https://www.bobvila.com/wp-content/uploads/2018/06/slow_sink-drain_ptrap.jpg>)
*Photo: Tom Fenenga for BobVila.com*

The U-trap under your sink (also called the P-trap) blocks toxic, foul-smelling sewer gases from traveling through the pipe into your home. You’ll need to open it up to remove any clog-causing remnants that have collected inside. To do this, first place a large bowl under the drain to catch any spilled water. Use a cloth to loosen one side of the U-trap, and then loosen the other side. Remove the trap, pour out any water into the bowl, clean the pipe, and replace the trap.

### Step 4: Use an enzyme drain cleaner to clear the drain of remaining residue.

![Hand in yellow rubber glove pour sewer pipe cleaner down the kitchen sink drain. Kitchen and drain cleaning work](<https://www.bobvila.com/wp-content/uploads/2015/07/iStock-1402635943.jpg>)
*Photo: iStock*

Once you have the U-trap reconnected, pour an enzyme drain cleaner down the drain to attack any residue that didn’t come off with the pipe snake or brush. [Green Gobbler’s enzyme cleaner](<https://www.amazon.com/dp/B079K94HHV/?tag=bv-how-to-get-rid-of-drain-flies-20>) has the added benefit of coating the walls of the pipe to prevent future blockages. Let the gel sit for the amount of time specified on the label, and then run more water down the drain to flush it out.

With their breeding ground wiped out, the adult flies will have nowhere left to deposit their eggs and should eventually disappear.

If drain flies are still a problem in your home after a week, assume that you didn’t adequately treat all the problem areas. Go back to Step 1 to determine which drains still have problems, and repeat the steps above to clear out the infested drains.

**RELATED: [The Best Plumbing Services in America, Vetted](<https://www.bobvila.com/articles/best-plumbing-services/>)**

## How to Prevent Drain Flies

![Hair on the plastic trap grate when draining water in the sink](<https://www.bobvila.com/wp-content/uploads/2015/07/iStock-1346052053.jpg>)
*Photo: iStock Photo: istockphoto.com*

If you follow the above steps, you should be able to rid your home of drain flies. To prevent the pesky critters from coming back, regularly clean your sinks, drains, and disposal and remove the built-up matter that attracts the flies. Also, fix any leaks as soon as you notice them, because sitting water also attracts to drain flies. Finally, use [sink strainers](<https://www.amazon.com/OXO-Good-Grips-Silicone-Strainer/dp/B000U0K5PU/?tag=bv-how-to-get-rid-of-drain-flies-20>) and [hair catchers](<https://www.amazon.com/OXO-Silicone-Protector-Pop-Up-Regular/dp/B00OCEBMFM/?tag=bv-how-to-get-rid-of-drain-flies-20>) to stop debris from entering the pipes and create potential breeding grounds.

## Final Thoughts

Ridding your home of drain flies is entirely achievable with the right methods. Just remember that patience is key and banishing drain flies completely may take time. To speed up the process, keep drains clean and dry, fix any plumbing leaks promptly, and use drain covers to prevent future infestations. By following the steps above, you can create a drain-fly-free space and keep these pests from popping up in your home.