This document outlines a validation protocol to establish a 72-hour hold time for various water quality parameters in collected water samples. The protocol involves testing samples initially and after 24, 48, and 72 hours of storage at 2-8°C for parameters like pH, conductivity, heavy metals, nitrates, TOC, microbial counts, and bacterial endotoxins. Acceptance criteria are based on meeting specifications for each water type. A final report will determine the validated hold time based on conclusion from the study results.