This presentation shares lessons from multiple real-world semiconductor water projects where late-stage design assumptions led to unexpected risks and costly changes. Using site-wide water and chemistry models, the speakers show how system-level data analysis can reveal hidden interactions between reclaim, UPW, wastewater, and abatement systems early in project planning. The case studies highlight how a holistic, data-driven approach helps teams test scenarios, manage risk, and make more confident decisions before committing to major investments.