It requires an interim performance assessment for BTL business of the sewerage rehabilitation which continues from 2005 till now. Means, It is necessary to make an interim performance assessment and an analysis of an business effect of the sewerage rehabilitation BTL projects which still continues, and we presented an improvement method of the new sewerage rehabilitation project in future. This paper has conducted an analysis of the business effect for 3 local government BTL projects which are completed and under operation as of now in Jincheon-Gun, Cheongju-Si and Gangjin-Gun. As a method of business effect analysis, we conducted a business effect of the 3 places using the index set which we previously set for the business effect analysis. The index set in this research was sectionalized to an improvement effect of operating wastewater treatment plant, an benefit effect of the direct cost, an benefit effect of the indirect cost and an environment friendly effect. We, in this paper, conducted an business effect analysis for 3 sewerage rehabilitation BTL projects which are completed or under operation recently as a demonstration, however we judge that an business effect analysis shall be conducted in a stage that a significant time for operation has passed since the completion of the construction in order to induce an actual business effect of the sewerage rehabilitation BTL project.