Irrigation scheduling systems can potentially be improved through the use of information on crop evapotranspiration and real-time soil moisture and irrigation data from wireless sensor networks. As part of the NASA Satellite Irrigation Management Support project, we used wireless sensor networks deployed in commercial agricultural fields across California to track precipitation, irrigation, soil moisture, and deep drainage, and to compute daily water budgets for multiple crops at the field scale. Here, we present findings on the efficacy and feasibility of using wireless sensor networks in commercial agricultural fields to monitor key components of crop water budgets. We also compare estimated crop evapotranspiration derived from wireless water budget sensor networks against estimates from surface renewal instrumentation and satellite-derived estimates from the NASA Terrestrial Observation and Prediction System. Results from this research will lead to a better understanding of how to apply satellite and ground based sensor data to support agricultural producers in optimizing irrigation scheduling.