Total water storage (TWS) is obtained by the gravity recovery and climate experiment (GRACE) satellite by measuring surface density changes. TWS provides valuable information about the water cycle on Earth and can play a useful role in water resource management studies. In this study, TWS of GRACE- Follow-On (FO) satellite from 2018 to 2020 has been studied. The western and central regions of Iran are in a better situation than other regions. Northwest, North, Northeast areas have a decreasing TWS trend of more than 5 cm. The western regions of Iran show an increasing trend and its value is about 3 cm. The southern regions of Iran have an almost constant annual TWS trend. TWS 2020 is similar to 2019.