In last a few decades since 1960s, the economic growth and national development of Korea are rapidly achieved, however these have resulted in a number of environmental problems. For example, the high growth of industralization and urbanization has caused the overuse of water and its contamination especially in four major rivers and their basins. On the other hand, the demand of clean water has been raised, as the living standards and environmental consciousness of people have increased. As one of efforts to address this issue, the expansion of sewerage facilities was launched in mid 1980s and it has been enhanced whenever environmental accidents have occurred such as phenol spill in 1991 causing odor of tap water and death of fish. Six general plans of water resource management to improve water water quality were made and 10.6 trillion Korean won (US$ 10.5 billion) was invested by the government from 1989 to 1997. As a result, 60.9% of sewage was treated by facilities in 1997. Despite the steady investment in sewerage facilities and significant efforts made by the government, water quality grew worse in water supply sources.