Many companies relate to their customers through sales or service locations. It is not unusual for them to use both a mystery shopping study and a satisfaction survey as part of their information system. Mystery shopping is a type of study where researchers become customers that experience and evaluate the quality of service delivered. Transactional surveys, on the other hand, measure customer satisfaction of customers following a service encounter. The purpose of this study is to combine transactional satisfaction surveys and mystery shopping studies in small areas in order to obtain more precise measures of customer satisfaction. Small area estimation has received a lot of attention in the statistical literature in recent years due to the growing demand for reliable statistics in small area. The study applies a small area linking model to data from Aguas Andinas S.A., a private water supply company that provides service to the metropolitan area of Santiago in Chile, which covers 1.5 million households. The combination of information reduces de variance of the estimates of customer satisfaction by 35%.