Sustainability relies on the balance between economic, social, and environmental objectives. Although seemingly divergent at times, the connections between them elucidate opportunities for improving different components simultaneously. In water distribution systems, aging infrastructure, insufficient funds, water scarcity, leakage, and high energy use have prompted the pursuit of sustainability through different strategies. These conditions demand improvement and create the opportunity to rethink the system. The present study proposes five separate decision support approaches that underlie a systems approach. These address current issues of North American water distribution systems and lessen the gap between research and application.

The first two focus on the interface between users and networks. The relation between user characteristics and demand is studied by building an integrated database to support planning, especially demand management. Data from three Ontario municipalities are used to define metrics, benchmarks, conservation targets, and user clusters. The relation between users and service requirements is further explored qualitatively through a survey on water user expectations, addressing the disconnection between utilities and stakeholders. Applied to the City of Guelph, it informs the utility of knowledge gaps and preferred solutions.

While these approaches concentrate on the needs of the stakeholders, inputs to more thorough planning, the next two assess the resulting systems. A set of energy metrics addresses the issue of inefficient energy use and provides indicators of system capacity, costs, and greenhouse gas emissions. The metrics are applied to the Toronto water network, and allow for the identification of specific areas for improvement. In order to further evaluate how complex networks respond to variations, a more comprehensive set of performance metrics are proposed and applied to two example networks.

The final approach seeks to improve the design process by reducing the computational intensity of optimization procedures and thereby allowing for the analysis of more system objectives and uncertainties. The procedure, applied to Anytown, uses shorter time cycles to approximate full costs of systems with varying loads. Overall, the approaches facilitate current-day decision-making by applying systems thinking to the development of new solutions that collect, integrate, analyse, and re-interpret readily available data and models.