Water security is a critical global concern due to its impact on future generations. This concept is multidisciplinary, combining not only water availability but also its quality, encompassing chemical, physical, and biological characteristics to ensure suitability and safety. Among these aspects, water quality is the central focus of water security, particularly considering intensified human activities that pose significant risks of contamination. Different practices in this area are increasing nowadays, which may compromise water quality. To address these challenges, innovative technologies such as microfluidics are gaining attention for accelerating analytical processes, thereby reducing the timeline of test procedures and enhancing monitoring efficiency. Microfluidic devices have arisen as powerful tools to detect environmental pollutants. These devices are portable, easy to use, cost-effective, and have rapid response capabilities. Their application extends across various fields, including monitoring of environmental matrices (water, air, and soil), as well as agricultural monitoring. This chapter explores the development and implementation of microfluidic devices for detecting and determining prominent contaminants such as pesticides, heavy metals, microorganisms, etc. A range of detection methods, including electrochemical, colourimetric, and fluorescent, is used in combination with these devices to implement analytical platforms for monitoring water quality.