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Background: Rotaviruses are widely distributed throughout the world and cause serious water-borne infections in infants, children, adults, and individuals with weakened immune systems. These viruses enter environmental waters via wastewater discharge and pose a serious risk to public health. Objectives: The purpose of the present study is to monitor human rotavirus levels in Ahvaz's water and wastewater treatment systems. Methods: This study used the grab sampling method to collect 60 samples from two water treatment systems (including raw water inlet points, filtration outlet, and clean water tank outlet) and 48 samples from the influent and effluent of a wastewater treatment system in Ahvaz city. Water samples were concentrated with a 0.2-µm membrane filter cartridge and polyethylene glycol in a centrifuge, while wastewater samples were concentrated with both pellet and two-phase methods. For rotavirus detection, RNA isolation, complementary DNA (cDNA) synthesis, and amplification were performed with RVA primer by reverse transcription polymerase chain reaction (RT-PCR). The genotyping of rotavirus was performed using the multiplex nested reverse transcription polymerase chain reaction (MN-RT-PCR). Results: Out of the total samples collected, rotavirus was identified in 45 samples (41.66%) using RT-PCR. The efficiency of water treatment plant systems was 75%, and the efficiency of wastewater treatment plant systems in removing rotavirus was 60%. There was no significant difference between the rotaviruses identified in the influent and effluent samples of wastewater in different months of the year (P = 0.626). The most abundant genotypes identified were G9 and G10, with frequencies of 40% and 5%, respectively. Conclusions: The results showed that the water and wastewater treatment systems in Ahvaz are not efficient in eliminating rotaviruses. Therefore, continuous monitoring of human rotaviruses in water and wastewater to assess the efficiency of treatment systems and identify circulating genotypes for the appropriate design of human vaccines is recommended. There is also a need to use more appropriate processes for the removal of infectious viruses, such as ozone disinfection.