This chapter covers the protocols for collecting, preserving, and analyzing water samples. Many of the analytical procedures used for analysis have been approved by federal authorities and organisations such as the Environmental Protection Agency (EPA). Obtaining analytical data that precisely depict the chemical composition of the water in situ is emphasized throughout and the methods implemented for analyzing are briefly presented. It covers the various analytical techniques implemented to determine the organics, inorganics, and radioactive materials. It also covers the toxicity test systems, requirements, evaluation, and their implementation. © 2022 John Wiley & Sons, Inc.