Water contamination is a significant problem in all over the world, and it is crucial to monitor the contaminating nutrients regularly for keeping the groundwater or drinking water safe. The nitrate ion has a remarkable impact on human health and the environment, and excessive use of this ion might damage the ecological system and the natural environments. Nitrate ions can be detected through various laboratory-based methods or in-situ sensor-based methods to develop a monitoring system. But for the last few years, the Interdigital sensor is used to detect the nitrate ions due to their reasonable fabrication costs and secure sensing mechanism. Some such sensors have high sensitivity with a reasonable limit of detection (LOD). Others might have a reasonable sensitivity with the reduced cost, where the proposed detection method uses a sensor-based portable sensing system. This chapter discusses the different working principles and fabrication methods of the Interdigital sensor for nitrate ions detection in water.