Hospitals are water-intensive facilities that must simultaneously assure reliable potable supply and consistent compliance at their wastewater treatment plants (IPAL/WWTP). Using the RSJD Dr. Amino Gondohutomo (Semarang) as a case study, we translate daily consumption into wastewater loading under a conventional 80/20 grey–blackwater split. The data records 221.80 m³/day of water demand, which implies about 174.91 m³/day domestic wastewater to the IPAL; these values allow a data-driven assessment rather than assumptions. The operation is constrained by two interlocking limits: an installed IPAL capacity of 240 m³/day and a wastewater discharge permit (IPLC) capping the daily effluent to 175 m³/day to Kali Gemah, creating a narrow hydraulic margin during peak-load days. We develop two indicators, (i) daily effluent-quota compliance and (ii) process loading relative to capacity, and test operational scenarios with and without equalization and controlled outflow. On the supply side, a planned full switch to PDAM (municipal water) in 2025 is documented, potentially reducing dependence on groundwater and improving upstream quality control. Effluent-quality monitoring shows most months in 2024 met domestic standards, with an October episode (coliforms, ammonia, phosphate) resolved via draining the disinfection basin and chlorine-dose adjustment, underscoring the importance of SOPs and QA/QC. We find that, although process capacity is ample, the daily discharge quota is tight; therefore, right-sized equalization (6–12 h of average flow) and day-sum outflow control are pivotal to maintain compliance, complemented by disciplined QA/QC and integrated debit monitoring. The PDAM switch further supports aquifer conservation and operational reliability.