The increasing demand for water resources and the limitations of freshwater availability have encouraged the development of sustainable water reuse strategies, particularly in high-consumption facilities such as hospitals. Reclaimed water from wastewater treatment plants (WWTPs) has potential as an alternative water source for cooling tower systems; however, challenges related to water quality, biological risks, and operational reliability remain. This study aims to identify global research trends, technological developments, and optimisation strategies for reclaimed water utilisation in hospital cooling tower applications. A systematic literature review combined with bibliometric analysis and systematic literature network analysis (SLNA) was conducted using Scopus database publications from 2020–2025. Data analysis was performed using VOSviewer and Orange Data Mining through keyword mapping, co-occurrence analysis, word cloud visualisation, and Latent Dirichlet Allocation (LDA) topic modelling. The results revealed that reclaimed water research is dominated by environmental science and engineering fields, with major themes focusing on wastewater treatment, membrane technology, water reuse, and sustainability. Advanced treatment systems, including membrane bioreactor, ultrafiltration, reverse osmosis, and disinfection processes, were identified as key approaches for improving reclaimed water quality. This study highlights that successful implementation of reclaimed water systems requires integrated consideration of technological, environmental, regulatory, and public health aspects to support sustainable hospital water management.