The positive externalities associated with the construction of the Hetch Hetchy Reservoir include:
- Providing a reliable and clean water supply for the City and County of San Francisco and surrounding areas, which supports public health and urban development.
- Generating hydroelectric power, contributing significantly to the electricity needs of San Francisco, thereby reducing reliance on fossil fuels.
- Enhancing tourism opportunities, as reservoirs and associated infrastructure can attract visitors and support local economies.
- Supporting the principle of "the greatest good for the greatest number" by supplying essential resources to millions, which benefits a wide population beyond just the immediate area.
- The project also demonstrated innovations in construction techniques and engineering, contributing to advancements in dam building and infrastructure development.
These external benefits reflect improvements in public utility, environmental management through engineering, and economic gains extending beyond the primary purpose of water storage and supply.
