As an agricultural country, Indonesia relies heavily on water availability through irrigation networks to support the agricultural sector. Therefore, developing irrigation channels is crucial to ensure food supply, even in areas far from rivers. The purpose of this study is to determine the maximum irrigation water requirements in the Tajum Irrigation Area using the KP-01 and Cropwat methods This research aims to determine the maximum irrigation water requirements in the Tajum Irrigation Area using both the KP-01 method and the Cropwat application. This study was conducted to compare the results of water requirement calculations in the Tajum Irrigation Area using the manual KP-01 method and the Cropwat application. The analysis results show a significant difference in the irrigation water requirements in the Tajum Irrigation Area when calculated using the manual KP-01 method and the Cropwat application. In general, the Cropwat method produces lower water requirement values compared to the KP-01 method. This difference is attributed to several factors, including differences in evapotranspiration assumptions, the use of more detailed climate data in Cropwat, and the inclusion of soil moisture correction in Cropwat. The calculated maximum irrigation water requirements using the Cropwat method are 1.94 liters per second per hectare in June, while the KP-01 method yields 3.61 liters per second per hectare in May.