Subsequently monthly hourly observation tables were card punched and also by data entry system up to 1979 and Choi (1980) published the results including harmonic analysis and MSL in connection with first order land leveling adjustment. Mean well sounding was performed to evaluate gauge performance by Van de Casteele diagram. The edited hourly values were then transferred to Office of Hydrographic Affairs in 1984 and afterwards all hourly values are maintained by NORI. At present Korea gage network comprise 50 stations for predictions. In 2009 quality check of past hourly gauge data are being performed firstly by tidal residual series and it shows that data are corrupted with incorrect timing during summer time and also clock timing errors, datum errors, etc. Some data editing strategy using Edserplo developed at BODC will be discussed along with data verification procedure using 1 minute data from NORI Chart Digitization Project in 2009.