Water quality in Han River and the major water sources has improved, maintaining 1-2 water grade while that of Nakdong, Geum and Seamjin rivers' tributaries recorded regional fluctuations.

Water quality of Paldang Lake in the upper stream of Han River improved from BOD level 1.7 mg/l to 1.6 mg/l, due to efforts for water quality improvement like cleaning rivers and monitoring pollutant discharge.

In Nakdong River watershed, chlorophyll-aconcentration has increased in streams like Goryeong and Namji due to warm water temperature; while the water quality of the rest streams slightly improved or maintained the same level.

Daechong Lake, the largest water source in central Korea located in Geum River watershed, maintained the first water grade, with BOD 1.0 mg/l. Water quality in upper stream of Geum River, like Okcheon and Cheongwon improved; whereas water quality of lower stream deteriorated.

In Yeongsan River watershed, the water quality deteriorated in most of its streams, due to increased concentration of organic matters like chlorophyll-a; however, Juam Lake maintained the first grade water quality with BOD 0.7 mg/l.