Urbanization has significantly increased impervious surfaces, generating contaminated runoff that contributes to urban water pollution. Roof runoff is a major source of non-point pollution, carrying pollutants such as heavy metals, organic matter, and nutrients into water bodies. This study explores the potential of using biochar produced through biomass pyrolysis, as a sustainable solution for improving roof runoff quality. Specifically, three biochar types (rice husk, coconut shell, and wood) were tested for their ability to remove pollutants from runoff collected from three different types of roofs namely metal, clay, and asbestos roofs. Performance of biochar were assessed based on several key properties, including particle size, water holding capacity, bulk density, and pore structure, all critical to biochar’s pollutant adsorption capacity. Improvement of the runoff quality was analysed based on laboratory-scale experiments conducted using filtration beds packed with uniform layers of biochar. Runoff samples were collected during rainfall events and analysed before and after treatment for various water quality parameters, including pH, Electrical Conductivity (EC), Turbidity, Total Solids (TS), Total Suspended Solids (TSS), and concentrations of heavy metals (Zn, Al). The results showed that coconut shell biochar performed the best across all parameters, exhibiting significant reductions in turbidity and TSS, making it ideal for stormwater treatment. Coconut shell biochar showed the overall best performance by effectively removing pollutants. Wood biochar demonstrated excellent performance in solids removal but resulted in higher EC and colour changes, which may limit its suitability for applications requiring clear water. Rice husk biochar maintained stable pH and EC but showed lower efficiency in removing solids. These findings underscore biochar’s potential as a cost-effective and sustainable material for improving stormwater quality, particularly in rainwater harvesting and groundwater recharge applications. Further research, particularly field-scale trials, is recommended to optimise biochar use in real-world applications and ensure its long-term effectiveness.