The detection and monitoring of pesticides in water are critical for environmental management and public health protection, as pesticides used in agriculture can contaminate water bodies through runoff, leaching, and direct application, posing risks to aquatic ecosystems and human health. Various sensor technologies, including electrochemical, optical, and biorecognition sensors, have been developed for efficient pesticide detection, offering advantages like cost-effectiveness, portability, and rapid response times. Among these, various biosensors (enzymatic, whole cell, immunosensors, DNA) show high sensitivity and specificity for detecting pesticides. Recent advancements in nanotechnology have further enhanced these sensors. Nanomaterials are used to amplify signals, increasing sensitivity and allowing for more accurate detection at lower concentrations. Additionally, nanoscale materials improve the performance by increasing their surface area and enhancing electron transfer rates, which boosts their sensitivity and response time. Integrating these advanced nanomaterials with traditional sensor technologies enables real-time monitoring of water contamination with greater accuracy, aiding timely interventions to mitigate risks. Incorporating nanotechnology into sensor development not only improves detection limits but also supports the development of portable and cost-effective solutions for on-site analysis. Combining these sensors with comprehensive monitoring programs and sustainable pesticide management practices is essential for preserving water quality and protecting ecosystems. Continued research in nanotechnology and sensor development is crucial for enhancing our ability to detect and manage pesticide pollution, ultimately safeguarding human and environmental health.