Wastewater utilities and municipalities typically make decisions based predominantly on economic variables, a defensible methodology given the importance of minimizing financial impacts and managing public money prudently. As our society progresses, however, utilities are expected to look for opportunities to make more comprehensive decisions that go beyond the traditional economic-based models. In response, some private and public entities are beginning partly or fully to adopt full-cost accounting systems.Full-cost accounting recognizes the important role of financial information in the transformation to more sustainable social systems. This paper will present a concept of how traditional financial accounting can be extended to consider sustainability impacts at the wastewater utility. The focus is on extending the range of monetized information to include externalities (covering environmental, social, and economic impacts) on which decisions are made. Full-cost accounting systems can provide wastewater professionals tools for communicating the value of the service provided. As utility managers begin to more comprehensively understand the value of wastewater treatment, the value of products can be more effectively understood and communicated to customers, and hence, more sustainable decisions can be made.