The effect of the increasing sea-level is the quality and source of fresh water. Particularly, for the Ban KhunSamut Chin,where is in a lowland coastal area, the rising in sea-level may cause the groundwater to increase as well. In this case, it will lead to the occurrence of impurities such as virus and bacteria from wastewater treatment system that may fall into the water. The problem can cause hazard to the local population not directly but indirect way if the dirty can enter the food chain.