In this paper we present the process of eliciting requirements for the a highly sensitive pervasive water monitoring photonic device, ranging from the review of the state of the art, to the design and conduction of surveys among key stakeholders (both internal to the project and external ones) who take interest in water quality monitoring, eventually leading to the elicitation of requirements that will drive the photonic device design and development. The photonic device will be developed in the context of the EU WaterSpy project.