Problem Statement: In general, the drinking water systems sourced from ground water (GW) contains chemicals at double the current maximum contaminant levels (MCL) of colloids. However, due to increasing demand of water, groundwater may be subjected to over-exploitation and the natural equilibrium is thus disturbed. A steady-state condition is established between seawater and freshwater in a coastal aquifer. This results in aggressive groundwater-surface water interaction, which may even reach the inland aquifer. Approach: The objectives of this research are to determine the level of contamination of groundwater by seawater intrusion and to identify its hazard. A flow model is created using the study area, Kanchong Darat in state of Selangor in West Malaysia in Visual MODFLOW environment. By a transient-state analysis the environmental impact due to groundwater pumping has been studied and the results of are obtained. Conclusion: The simulation results revealed that GW would get lower, and finally the interface between fresh and saltwater could gradually move inland if the abstraction of GW is continued and become over-exploited. In the model the drawdown (DD) at the top most aquifer (depth of 55 m) has been found with a depression cone of radii around 3650 m after 1 day of pumping; the radii reached 7500 m with depth of DD 55.5 m after 10 days, while after 30 days of pumping; it reached about 10 km with DD 56.8m. These models are useful for better water resource management and to understand the coastal hazards into inland resources wherein 75% of the water resource is based on groundwater system.