In this study, the potential to treat domestic wastewater (DWW) using an electrocoagulation (EC) process was tested on two different samples, one of which was heavily loaded [380 mg chemical oxygen demand (COD)/L]; the other was weakly loaded [260 mg COD/L]. The samples were supplied from the Istanbul-Yenikapi DWW pretreatment plant. The experimental studies were conducted within an electrolysis cell with Fe–Fe electrodes. In this cell, under optimum operational conditions in the form of electrical power and electrolysis time, pollutant removal efficiency (as COD), suspended solids (SS) and characteristics of formed sludge were tested. At the end of these studies, the optimum operational conditions found for electrical power was 0.6 W for both DWW samples, and electrolysis times were determined as 15 min for heavily loaded DWW (HLDWW) and 8 min for weakly loaded DWW (WLDWW). Energy consumption in optimum electrical charge conditions was 0.4 kWh/m³ HLDWW and 0.2 kWh/m³ WLDWW. The removal efficiency of COD and SS were obtained and shown to be over 60 and 70%, respectively. The level of sludge production was 1.5–2% during the optimal reaction time, and sludge volume was decreased 50% using H₂O₂.