I explore the relationship between humans and the freshwater mussel Unio tumidus from both ethnographic and ethical perspectives. These mussels are placed within the technological environment of water infrastructure, where their role is to help control the quality of water intended for human consumption. I investigate whether these interactions can be understood as labor relations, following Donna Haraway’s framework, or as exploitation, as conceptualized by Peter Singer’s utilitarianism. My aim is to contextualize these interspecies relationships within a broader framework that acknowledges each species’ unique knowledge, skills, and needs concerning water. This exploration also extends to the relationships among individuals whose work is intricately connected to water.