In the coal mining area, the pH of mine water is found tend to low and acids. In order to increase the pH, it is important to consider the treatment of acid mine drainage using lime, due the indicators of pollution. This work is focused on the influence of rainfall volume on the pH of acid mine drainage. This research conducted using a ratio of mine water and rainfall water that varies in the 9 (nine) conditions, respectively: 1: 1, 1: 2, 1: 3, 1: 4 and 1: 5 and 5: 4, 5: 3 , 5: 2 and 5: 1. The results were then measured and tested with statistical analysis. The ratio of rainfall and mine water showed a significant effect on the pH. The higher of the rainfall lead to increase pH. This condition will affect the water neutralization process using lime where there are some possible differences on dose of lime needed to neutralized the acid mine drainage in the rainy season and dry season.