The significant body of research on electrochemical wastewater treatment mediated by reactive chlorine species (RCS) still lack an experimentally accessible indicator that generally governs the current efficiency of RCS generation (CERCS), and mechanistic understanding on its deviation from current efficiency of chemical oxygen demand degradation (CECOD). This study investigated commercial anodes comprised of Ta-doped IrOx, Sb-Sn-doped IrOx, Ti-doped RuOx, PtOx, Ta-doped TiOx, and IrTaOx/TiO2 heterojunction, as confirmed by X-ray spectroscopic analyses, with diverse morphologies. The CERCS, measured in 50 mM NaCl solutions at 40 mA cm−2, could be described by experimentally accessible potential of zero charge (PZC) that is linked to the intrinsic surface property (charge density) of anode. In addition, CECOD was evaluated at 30 mA cm−2 for model contaminants and real wastewater including livestock wastewater, septic sludge, and septic tank effluent. A radical propagation with aromatic pollutants, dissolved O2 and cathodically generated H₂O₂ led to initial CECOD exceeding unity. However, the Janus-faced role of H₂O₂ as a sink for RCS could be underscored upon extended electrolysis. A non-targeted analysis by mass spectroscopy indicated that the highest CECOD for livestock wastewater was attributed to a predominance of low-molecular-weight organics, whereas CECOD for septic tank effluent was inferior due to dominance of hydrophobic macro-molecules. These integrated findings inform strategies for PZC-guided anode selection/optimization and cell design depending on wastewater composition, ultimately to advance the electrochemical wastewater treatment.​