The recent detection of plastics in drinking water sources, tap water, and groundwater can induce various emerging bottlenecks in global drinking water quality management. One of the main challenges is the leachates from the plastic pollutants that have the potential to invoke health and toxicity issues. There are no comprehensive studies currently addressing this issue. We use a technique based on the measurement of the dielectric properties of the samples, carried out using the rectangular cavity perturbation technique at the S-band of microwave frequency of 2–4 GHz to detect the presence of leachates in drinking water laced with plastic particles. Polyethylene Terephthalate (PET), High-Density Polyethylene (HDPE), Polyvinyl Chloride (PVC), Low-Density Polyethylene (LDPE), Polypropylene (PP), and Polystyrene are selected because these are the most used commercial plastic materials and are abundant as environmental pollutants. Further, purified drinking water is spiked with different polymers in the laboratory. We observed changes in electrical characteristics at microwave frequencies, such as absorption factor, dielectric constant, and dielectric loss tangent when there are plastic particles while treating drinking water using simple techniques such as boiling. The electrical properties change according to the type of commercial plastic material in the sample. This can be inferred due to the kind of leachates in the sample. The proposed microwave-based method used in this study is non-destructive, quick, and straightforward. The method can aid in the rapid detection of plastic-associated pollutants in drinking water before it is disseminated for supply. Plastic pollution is perceived as a significant crisis for one health mandate as plastic pollution impacts layers of biological function. The current study upholds the one health mandate and addresses various sustainable development goals. The emerging water-plastic-health nexus can be addressed effectively using rapid and real-time detection methods such as the one proposed in this study.