Assessing the effectiveness of activated carbon is essential for the optimal operation of water treatment systems. Traditional evaluation methods, although precise, are typically labor-intensive and require complex equipment This study introduces a novel application of the B.EL.D™ device, utilizing redox potential measurements to gauge the activation level of carbon filters—an approach not previously employed. We hypothesized that redox potential is a reliable indicator of activated carbon’s performance, a hypothesis that was rigorously validated through extensive testing against the standard iodine number test (ASTM D4607). Our analysis included both control and operational samples from ongoing water treatment processes over two years, confirming a definitive correlation between redox potential and carbon’s adsorptive capacity. The findings demonstrate the potential of our method as a rapid, accurate, and cost-effective alternative to current testing practices. Currently under patent consideration, this study marks a significant advancement towards improving the assessment of activated carbon filters, providing an efficient pathway for water treatment facilities and establishing the foundation for a predictive maintenance model.