Water is our most precious and most rapidly declining natural resource. We explore pervasive technology as an approach for promoting water conservation in public and private spaces. We hope to motivate immediate reduction in water use as well as higher-order behaviors (seeking new information, etc) through unobtrusive low-cost water flow sensing and several persuasive displays. Early prototypes were installed at public faucets and a private (shared) shower, logging water usage first without and then with ambient displays. This pilot study led to design iterations, culminating in long-term deployment of sensors in four private showers over the course of three weeks. Sensors first logged baseline water usage without visualization. Then, two display styles, ambient and numeric, were deployed in random order, each showing individual and average water consumption. Quantitative data along with participants' feedback contrast the effectiveness of numeric displays against abstract visualization in this very important domain of water conservation and public health.