A noisy toilet after flushing could be due to several reasons: Water pressure: High water pressure can cause a loud noise when water rapidly enters the tank. Faulty fill valve: If the fill valve isn’t functioning properly, it may produce noise during the refill process. Loose parts: Loose components within the tank, such as the flush valve or flapper, can cause vibrations and noise. Mineral buildup: Mineral deposits in the tank or pipes can amplify sound.