Our paper evaluates the technical condition of sewerage systems in the Czech Republic that are not properly operated and managed. These include municipalities that own the water infrastructure and operate the sewer network themselves. The selected assessed localities are municipalities of up to 1,000 inhabitants in the Czech Republic, which themselves operate sewerage systems aged 40-50 years. The aim of this paper is to compare and classify various defects in the sewerage systems joining risk analysis method and a proposed methodology corresponding to the applicable EN 13508-2 standard used to assess the condition of the sewerage systems and house connections. The evaluation and comparisons of the technical condition of the sewerage systems with the operating companies is the subject of this paper. Evaluation was done by multi-criteria analysis based on the risk analysis method: Failure Mode and Effects Analysis. The results of the assessment of the technical conditions classified into technical indicators of defects are unique in the Czech Republic and abroad.