The present limnological investigation was conducted to study zooplankton diversity in municipal wastewater-contaminated ponds in light of their contributions to the ecosystem. It is revealed by the present study that the physicochemical factors of the study sites are regulated by wastewater input and anthropogenic activities. A good number of zooplankton species thrived in these ponds (22 species of zooplankton, including 14 species of Rotifera, 3 species of Copepoda, 4 species of Cladocera, and a single species of Ostracoda), which suggests that the municipal wastewater, loaded with various nutrients, has influenced the zooplankton diversity and abundance. Site 3, a well-managed fishpond, showed the highest Shannon-Wiener diversity index value (2.303). Site 5, contaminated with organic waste matter from adjacent cattle sheds, showed the highest zooplankton abundance (1609.63 ind. L-1) and maximum dominance (0.472). Site-wise variations of diversity indices and statistical analyses support our findings. These ponds, although faced with serious threats of extinction by unscientific and unplanned urbanization policies, could very well be recognized as natural effluent treatment units within the municipal areas. Ponds of varied sizes in almost every municipal area of the lower Gangetic plains stabilize raw untreated domestic wastewater and encourage fish yield and the local economy.