Abstract
The reason for the leakage of water from facility is mainly put into three categolies. The first is many years of degradation. The second is construction by mistake. The third is careless miss when facility is mentenanced. Especially we paied attention to the construction by mistake. And we tested the hydraulic test and 200 times plusation test for the samples which were constructed by mistake on purpose. As the result, we confirmed that the leakage of water from the plug joint is depend on the structure of it. But we didn't clear the predominancy of plusatio test on this experiment.