Despite decades of research and huge investment, remote monitoring of the state of fresh and sea-water using all but the simplest sensors remains prohibitively expensive. As water metering and charges are increasingly implemented across Europe, can the ordinary person expect to obtain devices that can enable them to independently check the quality of their drinking water? Will citizens be able to share this data, and access other data related to their environment, like air quality? The signs are that they will, but the path forward is not straightforward. In this lecture I will discuss the current status of autonomous sensors for environmental monitoring, and speculate on the key breakthroughs that could drive a sensor 'revolution', which has the potential to place a vast amount of environmental information in the public domain.