The water demands of semiconductor fabs can exceed the capabilities of existing public infrastructure, including the production capability and treatment capacity of municipal water supply and wastewater treatment. On top of all this, advanced semiconductor fabrication requires more water than ever, while even older technologies have new requirements for greenhouse gas (GHG) abatement. New GHG scrubbers consume additional water and contribute a new chemistry stream to the wastewater in the fab. This presentation will show how the implementation of a digital twin led to better decision-making about resource consumption for a semiconductor facility.