DAF is an emerging technology in water treatment over the world. However there has been a difficulty to apply DAF in Korea. Water authority people working in the field worry about the limitation of DAF when specially in heavily rainy season. It is actually known that DAF has a limitation in removal of high turbidity such as over 100NTU. Occasionally the surface water in summer is climbing up to over 500NTU in Korea. Overcoming this kind of high turbidity problem in DAF was investigated using a pilot plant. Water samples having high turbidity were made by which debris and top soil of nearby hill were mixed with local surface water. High turbidities such as 100NTU, 300NTU, 50ONTU of the samples were lowered below 35NTU by a small pre-sedimentation tank having 20minutes of hydraulic retention time. Turbidities of the effluents of the presedimentation tank were down far below the upper limit of 100NTU in DAF. Around 40NTU of turbidity in the samples could be removed down below 2NTU by DAF. Thus it was concluded that high turbidity problem in DAF application could be solved with a small presedimentation tank.