The total water requirement of the plants in Mun River basin calculated in percentage is found that peanut and rice have the highest water requirement per ton at 22% and 21% respectively. Furthermore, it is found that cassava has the percentage of water requirement per ton only 1% (70 cubic meters). When the data of an irrigation water requirement is presented, it is found that peanut has the highest irrigation water requirement per ton. In addition, cassava has the percentage of the irrigation water requirement per ton at 1% (70 cubic meters).