The existence of life on Earth is primarily dependent on water. Rapid industrialization, population increase, unplanned urbanization, poor use of natural water resources, and human activity have all negatively impacted water quality. Environmental pollution is becoming more problematic in human life and the environment. Water pollution is mainly increasing quickly as a result of industrial wastewater discharge. The release of numerous organic/inorganic pollutants has increased steadily along with the development of anthropogenic activity. Heavy metals have been identified as one of the priority groups among the several kinds of pollutants because of their detrimental effects on the environment and animals. It is a class of metals and metalloids with an atomic density of more than 4000 kg/m3. Because of their toxicity, heavy metals such as Cu, Pb, Ni, Hg, and many more have been associated with several environmental issues. Even at very low concentrations, the accumulation of ions from these hazardous metals in humans can lead to significant health problems for individuals and the environment. Since they can concentrate and accumulate in a variety of stable forms, heavy metals introduced into the environment are a major source of concern. Heavy metal contamination is one of the worst environmental issues facing the world today. Consequently, it is crucial to monitor and detect heavy metals in wastewater continuously. Various conventional techniques can be applied to measure trace elements in wastewater. This article details heavy metal ions, their impact on human health, the detection technologies, and their working principles.