**Abstract**

Monitoring of water quality is controlled by policy and legislation and programmes of measures defining the approach. However, temporal and spatial frequency of monitoring is sometimes insufficient to meet the needs of water quality management. Therefore, there is a need for new and affordable technologies that can collect data on water quality in real time or near real time at high spatial frequency. These approaches will not replace the need to take a spot sample and report a result, but they can help with the decision-making process. This chapter looks at several novel sensing developments, the challenges that they are designed to address and the mechanism of sensing. The technologies represent a hierarchy of approaches from low-cost nonspecific sensing to very selective biosensor technologies. These systems are in different stages of development and application, but this shows the potential is bright for addressing the challenges related to water quality monitoring. These technologies when commercially available can add to the toolset for water monitoring. However, there are certain data gaps in small stream monitoring, nutrient monitoring in surface waters, and so on. Therefore, a disruptive approach involves citizen science in addressing these data gaps to help reach the SDG 6 goals.

**Keywords:** sensing, biosensors, microfluidics, multimodal data, water quality
