This paper investigates effects of interstage water injection on the performance of a GE Frame 7EA gas turbine using aerothermodynamic modeling. To accomplish this objective, a computational code, written in FORTRAN 90 language and developed by DIEM University of Bologna, has been used. The calculation procedure considers effects of evaporation of injected water within the compressor including droplets dynamics, which are necessary in order to fully evaluate effects of wet compression on the gas turbine performance. The robustness of the computational code is demonstrated by evaluating stage-by-stage compressor performance and the overall gas turbine performance in the presence of inlet evaporative fogging, overspray fogging, and interstage water injection. The presented results show that water injection location influences compressor stage loading redistribution differently. The plausible explanations to the observed trends of various performance parameters are presented in this paper.