Previous nuclear magnetic resonance (NMR) studies by Chen et al. (Magnetic Resonance in Medicine 50, 515-521 (2003)) have demonstrated that the water peaks in NMR experiments have been split into two resolved peaks at magic angle spinning due to the isotropic susceptibility shift. The first peak of spectrum rises due to a central core-atoms of water and the second peak is due to tightly packed cells surrounding the water. We present theoretically the atomic model which is based on three-level Λ-type and three level Ξ -cascade atomic configurations of the cell to study the dependency of susceptibility difference on the splitting of water peaks. In addition, we study the effect of the strength of the magnetic field, the magic spinning angle, the electric field, and detunings on the splitting of water peaks.