Water is an essential component of life and a critical resource for environmental, industrial, and domestic applications. Understanding its physico-chemical properties is fundamental for assessing water quality, managing resources, and addressing environmental challenges. This review provides a comprehensive analysis of the key physico-chemical parameters of water, including temperature, pH, electrical conductivity, total dissolved solids (TDS), turbidity, and concentrations of major cations and anions. It discusses the methodologies employed for their measurement, highlighting advancements in analytical techniques and emerging technologies. The paper also explores trends in water quality studies across diverse ecosystems, emphasizing the impact of anthropogenic activities, climate change, and natural processes on these parameters. Furthermore, it examines the practical applications of physico-chemical assessments in areas such as drinking water safety, wastewater treatment, agricultural irrigation, and industrial processes. This review underscores the significance of integrating modern analytical methods with traditional approaches to achieve a holistic understanding of water quality. It also identifies research gaps and proposes directions for future studies to enhance the sustainability and management of water resources. By bridging the knowledge of methods, trends, and applications, this paper contributes to the broader goal of ensuring water security and ecological health in a changing world.