With the advent of the digital era, the necessity and desire to understand the environment, particularly the quality of one's local water and air, has only grown. Collecting enough data on a wide range of contaminants of environmental significance has replaced being able to store all of the obtained data as the barrier in comprehending the environment. A group of technologies that have been developed over the past 15 years for the highly accurate and sensitive detection of environmental pollutants includes nanomaterial enabled sensors. The ability to statistically grasp nature in a systematic way will soon be a reality because to the promise of simple, affordable, field deployable technology. The application of nano-sensors for the detection of three groups of environmental contaminants-pesticides, heavy metals and pathogens are explored in this review after a brief introduction to nano-sensor design.