Thesis (PhD(Civil Engineering))--University of South Australia, 2021. Includes bibliographical references (pages 206-233) The title of this thesis is system performance and economic feasibility assessment of conventional and hybrid stormwater drainage systems. The overall aim of this research was to investigate the economic feasibility of a stormwater drainage system that incorporates WSUD technologies at allotment scale (a hybrid system) over a conventional drainage system by considering life cycle costs, and direct and indirect benefits of the systems. Detailed economic analyses of WSUD systems indicated that a rainwater tank was the most economic WSUD technology for effective stormwater management and recommended the installation of rainwater tank in low–medium clay soil condition where other infiltration systems failed to satisfy either one or both design criteria. The results concluded that WSUD systems were economically feasible for all soil types in consideration with total benefits.