Small, dark brown worms of about 0.6cm (roughly 0.2-inches) have been popping up in the bathrooms and kitchen of this reader’s townhouse. Our reader tends to find multiple at a time in the kitchen, but only one at a time in the bathroom, and has been finding these worms for about a year now.
The photograph our reader sent in displays exactly what she was describing, a small brown worm, but not more than that. A higher resolution photograph — or one that was taken closer to the organism — would be required for us to make out the details of its characteristics. Regardless, based on the location of its discovery, as well as its size, we think it is safe to say that this is a drain fly larva.
Drain flies, otherwise known as moth flies or drain moths, are small, furry flies that are usually brown or gray in color in their adult stage. They are often mistaken for moths, hence their alternative names, but are indeed flies. In their larval stage, they tend to be black or brown in color, and can be striped too. As their name suggests, drain fly larvae tend to come up people’s drains. This is because the diet of the drain fly larva consists primarily of decomposing organic matter, plenty of which can be found in a pipe system. Homes are prone to drain fly infestations when a room with a drain (such as a bathroom or kitchen) has been neglected for a period of time. Usually this is because the residents of the home have been on vacation for a period of time and left the home unattended, and thus the faucets have not been run for a while, or that the given room’s drains are not consistently cleaned.
In the case of our reader, it could be that the kitchen’s drains are not cleaned as consistently as the bathroom’s drains, and so there is more of a build up of organic matter for the drain fly larvae to be attracted to. It could also be that our reader throws a lot of food down the garbage disposal, and perhaps some residue gets stuck on the inside walls of the pipe, thus creating a build up of organic matter. Either way, the process for eliminating the infestation is the same.
To begin with, our reader should manually remove any roaming larvae and take them outside. Unfortunately, there is no way to beckon the larvae to crawl back down the pipes that we are aware of. Then, what she will want to do is simply run the faucet on the hottest setting (using boiling water is also an option) for a while. Then, pour bleach (or any other safe, drain-cleaning chemical) down the drain to clean it out. Our reader will also want to check for a fine layer of film at the top of the drain that tends to form near the lip of the drain and destroy it (a brush and some hot water should do). This is where drain flies will lay their eggs to further spread the infestation, so removing this is probably the most important step! All of these steps should then be repeated every other day for a period of one-to-two weeks, depending on how severe the infestation is, though we recommend doing it for two just to be safe. To prevent further infestations, we recommend that our reader ensures that she sticks to a consistent cleaning routine. Pouring bleach down the drains once a week after running the hot water should do it!
In conclusion, the dark brown worms our reader has been finding in her bathrooms and kitchen are drain fly larvae. These critters do not pose a health threat, but they are nonetheless an unwelcome guest in the home. Despite it seeming as if our reader is experiencing an infestation (given the number of larvae she has found and the extensive period of time she has been finding these creatures), we are sure that if she applies the methods of controlling the infestation detailed above, she will be rid of this nuisance in no time! We wish her the best of luck.