The Kumamoto earthquake in 2016 caused damage to many water tanks. Sloshing caused by slightly longer-period seismic motion and bulging caused by shorter-period seismic motion are possible causes of damage to water tanks due to earthquakes. Since the periodic characteristics of seismic motions are greatly affected by the amplification characteristics of the surface soil, the damage to the water tanks is expected to be greatly affected by the ground characteristics. Therefore, this study evaluated the relationship between water tank damage and ground characteristics, and assessed the risk of damage to water tanks for earthquakes that are expected to occur in the future. The results showed that there is some relationship between water tank damage and ground characteristics, and that analysis of ground characteristics may be used to assess the risk of water tank damage.