One of the main issues that geotechnical engineers in practice around the world are concerned with is slope stability issues. Due to the change in pore water pressure caused by the existence of a water table, soil behavior becomes more complex. For the purpose of resolving any slope stability issue, the consideration of the rise in pore pressure caused by the cyclic nature of seismic forces has not been taken into account in prior studies. The current study takes into account Janbu's method of slices for the analysis and Skempton's equation for determining the excess pore pressure to examine the impact of pore water pressure on the factor of safety of both unreinforced and reinforced slopes. The quantity of nails needed to increase the safety factor to the appropriate level.