Municipal wastewater is the main contributor to diverse water pollution problems. In order to prevent the pollution risks, wastewater have to be treated before discharged to the main water. Selection of appropriated treatment process need the characteristic information of wastewater as design consideration. This study aims to analyse the physicochemical characteristic of municipal wastewater from inlet and outlet of ABR unit around Surabaya City. Medokan Semampir and Genteng Candi Rejo has been selected as wastewater sampling point. The samples were analysed in laboratory with parameters, such as pH, TSS, COD, BOD, NH4+, NO3-, NO2-, P, and detergent. The results showed that all parameters in both locations are under the national standard of discharged water quality. In other words, the treated water is securely discharged to the river