Large scale industrial complex and housing construction on soft clay is a growing trend in domestic western and southern coasts and ground improvement becomes a rising issue as an indispensable process in such construction. Piezocone tests, being applied actively in recent to evaluate improved effect of original soft ground by appropriate improvement construction to each area, is being widely used for soft ground investigation as a highly reliable field test. Piezocone test has huge range of applications since it can identify various geotechnical characteristics such as soil classification, coefficient of consolidation, overconsolidation ratio, undrained shear strength, angle of internal friction, hydraulic conductivity, and so on. Specifically, piezocone dissipation test has good reliability since it provides information regarding consolidation and hydraulic permeability through the dissipation of excess pore water pressure when the inter-penetrated piezocone is temporarily halted. This paper presents the results of piezocone test and Rowe cell consolidation test for 10 representative soft ground regions in domestic western, southern and eastern coasts, where researches on horizontal hydraulic conductivity estimation are barely performed. Plus, we evaluated the validity of previous hydraulic conductivity estimation methods by applying them to domestic ground and proposed a new hydraulic conductivity estimation formula optimized for domestic ground. The deviation in hydraulic conductivity estimation by the proposed formula varies in the range of 0.1 to 10 times proving much higher reliability than previous estimation methods. In the aspect of practical application to domestic soft ground, our experimental estimation was accurate in southern coast (Gimhae Jin-young and Yangsan Mul-gum) and western coast (Phyungteck Pho-seung). We conclude that our novel estimation formula is highly applicable to estimate hydraulic conductivity for domestic clay ground.