Yes, supposed to be found in water. We don't let her drink from puddles when we walk her. In our back yard, is another story. If she digs holes, there'll be puddles when it rains. She's had this ever since she was a puppy. I'm thinking she just has a really entrenched case that the flagyl that the vet prescribes just isn't taking care of, so I'm going to repeat the humaworm.