Drain Worms: Everything You Need to Know

If you come across small black worms in your bathroom, kitchen sink, or toilet, you may have a drain worm problem. These small black or brown worms are also referred to as “drain fly worms” or “drain fly larvae.”

what are drain worms comic

They can be a nuisance with potential health risks because they can spread bacteria. When left untreated, larva will mature and you will have a fly problem!

What are drain worms?

Drain worms are essentially fly larvae. These species are also known as sewer flies, filter flies, or sink flies. They lay eggs, which hatch into larvae within 32 – 48 hours. Their life cycles are fairly short. Also note that drain flies do not lay eggs in humans.

The larvae live for 8 – 24 days before entering the pupal stage for 1 – 2 days before becoming adult flies.

Top Rated Products for Drain Fly Removal

Linked below. Please also ensure you understand how to use these! Make sure you found the correct infestation source, and that the buildup in pipes or drains is actually removed. You can do this with a pipe brush.
Bestseller No. 1
InVade Bio Drain 1 Gallon (Original Version)
  • Microbes and Citrus Oil
  • This product is to be used specifically for drains but can also be used to eliminate sugar snakes in soda fountain drip trays. It is also safe and…
Bestseller No. 2
Rockwell – IBDC128 – InVade Bio Drain Gel -1 Gallon
  • Active Ingredient: Microbes and Citrus Oil
  • Target pests: Eliminates Odors, Drain Flies, Phorid Flies, Fruit Flies, and prevention of “Sugar Snake”

Video of live drain worms (drain fly larva):

Larvae feed on sewage and decaying organic matter and measure about 4 – 10mm long. They are slender with a dark stripe on the dorsal areas reason why they appear black. 

If you take a closer look, you might see subtle brown and black stripes. Larvae do not have eyes, are legless, and have a dark breathing tube on one end that they use to obtain air by extending it out of the film. (Yum.)

What causes drain worms?

Drain worms live in and feed on decaying organic materials, including human hair and skin cells. They thrive in places with high moisture, including pipes, p-traps in plumbing fixtures, and standing water. Most people visiting our website have this issue in their bathroom shower, sink or sump pit.

Stagnant water also presents an ideal breeding ground, the reason why you will tend to spot them when coming back to a house that has been vacant for a few days. 

drain fly larva worm
Source: Matt Bertone, NC State

If they appear, it means you need to spend more time cleaning out your drains. However, drain worms don’t necessarily mean dirty pipes. You could also be having a plumbing problem such as a leaking pipe that leads to an accumulation of stagnant water, which provides an ideal breeding ground.

In more extreme cases, a sewer line break beneath your home 

Where are drain fly larvae commonly found?

You can typically find drain worms in drains, showers, sinks, toilets, underneath shampoo bottles, in air conditioner pipes, around garbage bags, or in areas where rainwater accumulates.

It is common for them to be active in septic tanks, which is usually a sign of a healthy tank!

How to identify a worm infestation in your sewers or toilet?

Not all worms are drain worms. Hence, before you start looking for a solution to get rid of them, it’s important to confirm that you have drain worms.

drain larva in toilet goodbye drain flies

The presence of adult drain flies is a telling sign of the existence of larva. Even if you cannot see them. 

If you are unsure whether you have drain flies, place some sticky tape over the drain in a room where the drain flies are present or where you spotted the worms. Leave this for a few hours before checking to see if there are flies or worms attached to it. The worms are nocturnal, so do this at night when they are active.

How to get rid of drain worms

Given the potential health risks associated with drain worms, it makes sense to get rid of them. Destroying the breeding grounds is the most efficient way to get rid of these worms.

Clean the drain pipes

Scrub the outside of the drain pipes to loosen and get rid of sludge. Clean the inside of the pipes using a metal pipe to remove organic build-up and excess waste, then rinse with hot water.

Cleaning the pipes ensures you destroy destroying the worms feeding ground. They will die off in a couple of weeks. Note if you have a drain fly problem in you RV, the process of removal is a little different.

Use enzyme drain cleaners

Enzyme cleaners use enzymes or bacteria that eat through organic material in the pipes destroying breeding grounds.  Examples of enzyme drain cleaners include Green Gobbler, which works as a complete clog-removing kit.

Drano Max Build-up Remover or the Drano Max Gel Clog Remover helps prevent clogs forming in your pipes. Apply the drain cleaners as per the instructions for the best results.

Drano Gel gel for flies

Kill the adult flies

Even after getting rid of larvae for the pipes, the adult flies can lay more eggs; thus, eliminating them is crucial. Spray aerosols insecticides directly at the flies or use fly traps and swatters—also, DIY methods including mixing liquid dish soap with water or apple cider vinegar trap.

Routine maintenance

Prevention is the best way to avoid having to deal with this issue again! Keep all drains in the house clean by using simple measures as pouring half a cup of baking soda into each, followed by an equal amount of white vinegar. You can also opt for a bio gel, such as invade.

bio drain gel goodbyedrainflies

Let the mixture form for several minutes, then run hot water to rinse the pipes. Run hot water through less frequently used drains, either once or twice a week, and keep up with septic system maintenance.


Final thoughts

Removing organic build-up is the best way to eliminate drain worms because it destroys their breeding and feeding sites. To prevent this issue altogether, always keep sinks and other areas clean, flush pipes by pouring water down them on occasion and undertake routine maintenance as is required in food establishments.

While it is common for infestations ito occur in home bathrooms and showers, using a non-harsh drain cleaner to emove organic buildup can help prevent issues down the line.

Last update on 2024-04-16 / Affiliate links / Images from Amazon Product Advertising API