The Massachusetts Water Resources Authority (MWRA), like many water suppliers across the country has embarked on several major infrastructure improvement programs to take an essentially 19th century, regional water system and bring it into the 21st century. The need to build a new water treatment plant, construct an 18 mile deep-rock water transmission line as well as prepare for the removal of open distribution reservoirs provided a significant challenge in highly developed suburban Boston. The focus of this paper is to detail how the MWRA organized, supported and incorporated citizen participation to build an alliance of stakeholders during the environmental review, design and construction phases of these projects.