Recently a great deal of people are taking legal action against the housing provider due to the defects of their Apartment house. And most of the housing companies are spending a huge amount of expenses and efforts to keep their brand value. This essay will carry out time series analysis the 20 housing district which are constructed by huge construction companies. This analysis itemised by metropolitan area(Seoul) and others to keep the degree of reliability, and converted future defect maintenance cost into current cost applied by discount rate to figure out suitability of defect maintenance cost. Even though, this essay is not able to represent standard of defect maintenance cost due to the insufficiency of record, while it will be assisted as a referance when long-term record of time series is estabilished.