“I found this on our water while I was filling the tub”, states this reader in her query concerning the black worm pictured below. She is not sure if they are leeches or something else, and wants to know if it is harmful.

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.

Several gray-brown worms were found by this man’s son in their bathtub after not having been home for several weeks. Our reader, who is based in a basement apartment in London says he would appreciate any thoughts on what the worm is, how it got there, and how to prevent their return.