This research aims to establish a gravity-based aeration system for raw water in the water supply process at Rajabhat Mahasarakham University. The objectives included evaluating the system's effectiveness for oxygen transfer and developing a suitable model for water supply applications. The study assessed various water quality parameters, including total suspended solids (TSS), biochemical oxygen demand (BOD5), and total coliform bacteria. In a series of six tests conducted at monthly intervals between 09:00 and 09:30 a.m., both inlet and outlet water were collected for a total of 12 samples. Results revealed that the gravity-based aeration system could reduce suspended solids by 54.87%. The average BOD5 of water at inlet and outlet was found to be 7.10 mg/L and 6.88 mg/L, respectively, indicating a 3.04% reduction in BOD5. Moreover, the gravity-based aeration system could reduce total coliform bacteria by 82.26%. To maximize the system's efficiency in eliminating total coliform bacteria, it is recommended to operate the system under optimal conditions and regularly clean the sediment tank when the system is shut down.