Climate change may lead to increased turbidity in Japan's water supply. A study tested water treatment systems using sand and membrane filtration with coagulation. Results showed that membrane filtration was more effective at handling high turbidity levels than sand filtration. Increasing coagulant dosage improved filtration efficiency, with polyaluminum chloride at 72% basicity performing better than at 51%. Sand filtration struggled initially but improved with higher coagulant levels. Overall, membrane filtration proved more resilient to sudden increases in turbidity.