Small Worms in Toilet After a Vacation

“Where did they come from?” This is the first question you would likely ask if you found small worms in the toilet after a vacation. The second question would be how to eliminate them and prevent a future reoccurrence.

plane flying in the air from vacation

Many worms thrive in stagnant water containing organic matter, and your toilet bowl presents the ideal environment. Proper identification of the worms is the first step toward getting rid of them effectively.

Drain worm larvae, bloodworms, and horsehair worms are the most common types of worms you might encounter in your toilet.

Getting rid of some worms, such as bloodworms, may be as easy as cleaning your bathroom thoroughly. However, you may need professional help to get rid of other types of worms. For example, since earthworms live in the soil, their entry points are likely underground. You may need a certified professional plumber to check all your sewer lines to identify and fix all possible entry points.

Drain Fly Larvae

These are small black worms, also referred to as drain worms. They are the most common types of worms you might find in your toilet bowl after a vacation. They eventually turn into drain flies, also known as sewer flies, filter flies, or sink flies.

drain fly larva

Adult drain flies lay clusters of about ten to two hundred eggs in moist organic matter, which hatch into larvae in about 48 hours. Drain worms have a dark stripe on their dorsal area and a noticeable dark breathing tube on one end. They will only grow to about 10 mm (or about 3/8 of an inch) long and will live for nine to fifteen days before pupating into adult flies.

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Drain worms feed on sewage and decaying organic matter and thrive in places with high moisture, such as drains, septic tanks, sewer pipes, sump pits and plumbing fixtures. Stagnant, shallow water provides the ideal breeding ground for them, so you will most likely find them in toilets that are infrequently used.

The presence of drain worms in your toilet may indicate a drain fly infestation in your plumbing, or a crack in your sewer line.

How to get rid of drain fly larvae

To effectively eliminate drain worms, you need to destroy their breeding ground.

  • Start by identifying the source. Adult drain flies tend to hover around their breeding grounds. So cover drains near where you have seen the adult drain flies with sticky tape, with the sticky side of the tape facing downwards. Leave it overnight. Drain flies on the tape means that you have found their source. (Note that toilets may also be a source of flies if adults travel up from your main sewer line and enter through a broken wax seal.)
  • Clean the drain pipes inside and outside to eliminate any organic buildup. You can use several DIY solutions or store-bought products to remove and prevent clogs from forming in your pipes. DIY solutions include pouring a hot water, baking soda, and vinegar mixture down the drain or scouring the drain with a metal pipe brush to dislodge any organic matter. Store-bought products that you can use include enzyme drain cleaners such as Green Gobbler, Drano Max Build-Up Remover, and Drano Max Gel Clog Remover.
  • Kill adult flies using insecticides, insect growth regulators, fly traps, zappers, or DIY methods.
  • Routinely maintain your pipes to prevent reoccurrence.


Bloodworms are nonbiting midge fly larvae that eventually mature into adult midge flies. They are bright red and can grow up to 35 cm (14 inches) long. Their bright red color is from high levels of iron-porphyrin protein in their blood and tissues. These high iron-porphyrin levels mean that bloodworms don’t need a lot of oxygen, which is why they can thrive in stagnant and contaminated water with low oxygen levels.

bloodworms in bucket

Because they feed on organic matter, you will likely find bloodworms near water sources like sinks, bathtubs, or toilets that are not often used. Bloodworms are not harmful to humans, but their presence may indicate that something is wrong with your water or that you need to thoroughly clean your toilet.

How to get rid of bloodworms

The best way to prevent bloodworms is to keep your toilet clean. Use a disinfecting cleaning product, such as bleach, and a brush. If you prefer a chemical-free approach, use a baking soda and white vinegar solution with a brush. With no organic matter to feed on, the bloodworms won’t survive. You can also physically remove the worms and dispose of them, or you can use curry or powdered salt to kill them.

Horsehair Worms

Horsehair worms are also known as Gordian worms. They frequently appear in masses of more than 100 worms, forming into a twisted knotted ball that looks like a Gordian knot. hence the nickname Gordian worms. You can easily mistake them for a ball of hair. They are deep brown or yellow and can reach 10 to 35 mm (4 to 14 inches) long but are only 1 mm (1/25 inch) in diameter.

Once the adult female worms lay eggs, the eggs hatch into larvae in two to four weeks. The larvae then find a host to parasitize. After about ninety days of living inside a host insect, mature horsehair worms will emerge and swim off when their host finds water.

Typical hosts include cockroaches, grasshoppers, beetles, and crickets. Horsehair worms are not parasitic to humans or pets. Horsehair worm eggs end up in the toilet bowl through these insects, which means you may be dealing with another infestation. Also, mature horsehair worms mate in water, making your toilet bowl an ideal location.

It’s also common for these parasitic worms to appear when temperatures drop. Insects carrying them usually retreat inside buildings, including your home, to find warm places to overwinter.

How to get rid of horsehair worms

Kill the ones already in your toilet bowl using toilet lotion, curry, or powdered salt. You can also spray the toilet bowl with disinfectant or use store-bought products. To prevent reoccurrence, caulk and seal all possible entry points around your house to prevent various insects from accessing it.

How to Prevent Small Worms in Your Toilet Bowl

There is no guarantee that worms or other pests won’t appear in your toilet bowl. However, there are preventative measures you can take to ensure they don’t reappear. While specific prevention measures will depend on the worm species, good general preventative measures include:

  • flushing toilets that you don’t frequently use at least once or twice a week.
  • keeping your bathroom clean and dry. ensuring your bathroom is well-ventilated to prevent moisture and mildew, which provides an ideal environment for worms to thrive in.
  • spraying your toilet and other bathroom surfaces with vinegar monthly, as it will help to kill the eggs.
  • regularly cleaning and maintaining your drains to ensure there is no buildup of organic material.
  • ensuring you seal all possible entryways that worms or insects can use to access your house.

Last update on 2023-09-25 / Affiliate links / Images from Amazon Product Advertising API