“We found these little tiny black worms in our bathtub and was wondering what they are,” states this reader in his submission. From the pictures he sent us, we can see that the worms look more brown than they do black, with horizontal stripes running along their bodies and dark tips at either end.
No more context is provided by our reader, but the pictures he sent us are clear, and for that we are grateful. Because of the pictures, and the location in which they were found, it is clear to us that these are drain fly larvae. Drain flies, commonly known as moth flies because of the adult’s moth-like appearance, are common household pests who lay eggs on the thin film of organic matter that forms in drains when they have been left uncleaned for a long period of time. From those eggs hence come the larvae, which is what our reader found. One is most likely to find drain fly larvae in their bathroom after a period of neglect, such as a long vacation.
Drain fly larvae do not strictly cause any direct harm to the household or its residents, but they can be unsettling to have roaming one’s bathroom and simply not too pleasant to have around uninvited. Once they have inhabited one’s bathroom, it is quite easy for an infestation to begin. This is not only because the mother fly can lay up to 100 eggs at a time, but also because their breeding sites can go largely undetected for long periods of time. DIY Pest Control’s page on drain fly larvae suggests that drain flies can also set up breeding sites underneath the floor of one’s bathroom if a pipe has broken. In the case that our reader thinks he is experiencing a severe infestation and he does not think the source of it is the drains themselves, then we recommend that our reader check out their website; their pool of information on drain fly larvae is vast and can prove very helpful.
If the drain flies do seem to be coming from the drains, and one can test this by putting tape over the drain and waiting for moth flies to get trapped (a tip we learned from DIY Pest Control), then the process one should undergo to get rid of them is quite simple. The first step is locating the breeding site of the drain flies, which our reader already seems to have done. In the bathtub drain there should be an organic film that our reader can scrape away using a knife or brush (making sure the bristles are hard). Steel wool would also do well. Our reader should then clean his drains as one normally would using whatever viable materials he wants to (bleach and hot water, baking soda and boiling water, etc.), and he should repeat this several times a week for at least two weeks. He should also make sure to sanitize all the surfaces of the bathroom a few times a week as well, so as to prevent the build up of organic matter in other places as well. This will further discourage the drain flies from coming back. Roaming flies and larvae can be moved outside, though there is a risk of them finding their way back into our reader’s home (unless he takes them far away from his home). Hence, we will not pass judgement if our reader uses more convenient methods of disposing the flies and larvae. Lastly, our reader should make sure that all the drains in the rest of his home are similarly cleaned, as this will prevent the drain flies from expanding and creating more breeding sites, and will eliminate any sites that may already have been established.
To conclude, the “little tiny black worms” in our reader’s bathtub are drain fly larvae. They may not be a threat to our reader’s health, but the risk of infestation is high, so we nonetheless urge our reader to make haste and deal with this as soon as possible, before it becomes a bigger problem. We hope our article proves helpful to our reader and we wish him the best of luck.