Particularly in research related to seawater intrusion the change of fluid electrical conductivity is one of major concerns, and effective monitoring can help to optimize a water pumping performance in coastal areas. Special considerations should be given to the mounting of sensors at proper depth during the monitoring design since the vertical distribution of fluid electrical conductivity is sensitive to the characteristics of seawater intrusion zone. This tells us the multi-channel electrical conductivity monitoring is of paramount consequence. It, however, is a rare event when this approach becomes routinely available in that commonly used commercial stand-alone type sensors are very expensive and inadequate for a long term monitoring of electrical conductivity or water level due to their restricted storage and difficulty of real-time control. For this reason, we have developed a real-time monitoring system that could meet these requirements. This system is user friendly, cost-effective, and easy to control measurement parameters - sampling interval, acquisition range, and others. And this devised system has been utilized for the electrical conductivity monitoring in boreholes, Yeonggwang-gun, Korea. Monitoring has been consecutively executed for 24 hours, and the responses of electrical conductivity at some channels have been regularly increased or decreased while pumping up water. It, with well logging data implemented before/after pumping water, verifies that electrical conductivity changes in the specified depths originate from fluid movements through sand layer or permeable fractured rock. Eventually, the multi-channel electrical conductivity monitoring system makes an effective key to secure groundwater resources in coastal areas.