This study comprises the design of rectangular underground water tanks under different ground conditions and the strength analysis of slab floor, walls, and foundation of rectangular underground water tanks. The importance and sustainability of water storage and management for humans is a very important and detailed issue. In this research, the design and analysis of rectangular water tanks to be constructed in ZA and ZE ground classes classified according to the Turkish earthquake regulation (TBDY 2018) were made using the IdeCAD program. The results of the stress, moment and deformation analyzes according to the design made with the design parameters used in this research showed that the rectangular water tanks to be built in the ZA ground class have structural strength against the stresses arising from soil, water and earthquake loads without suffering any significant deformation. The design values obtained using stress, deformation, and structure overturning moment analyses were found to be with in the limits of structural safety confirming the reliability of the design parameters. On the other hand, it has been found that underground water tanks to be built in the ZE soil class could also successfully resist to the lateral overburden and earthquake loads. However, it was determined that the deformations in the tank structure in ZE class soil were found higher than in the ZA class soil due to th e loose, weathered, and low bearing strength of the ZE class soils. This study also emphasizes the importance of using raft foundations under underground water tanks to be built on ZE class grounds to increase safety and prevent increasing deformations over time, such as creep.
