The purpose of this study is to evaluate the effect of considering seismic forces in the design of frame-type supporting structures for elevated water tanks (EWTs), and to assess the influence of fluid–structure interaction (FSI) on the overall structural response. Firstly, the developed finite element model is validated in accordance with American Concrete Institute code. Secondly, push-over analysis (POA) is performed to evaluate the performance of EWTs for frame members that are designed based on governing seismic and/or gravity loads. From the POA, the formation of plastic hinges is observed in the frame members, and the lateral stiffness and ductility factor is evaluated for each structure. After that, incremental dynamic analysis is conducted by subjecting the EWTs to a suite of ground motions with different intensities and site–source distances to investigate the influence of including FSI in the EWT analysis. Based on the results, the seismic design of the staging contributes to improvements in terms of the stiffness and ductility of reinforced concrete staging. Additionally, the inclusion of FSI introduces a high nonlinearity to the EWT analysis and can drastically change the response of the structure based on the characteristics of the ground motion.