Coal remains a critical global energy resource; however, its extraction and processing generate substantial volumes of coal mining wastewater, posing serious environmental challenges. Effectively recycling this industrial by-product is essential for mitigating ecological impacts and promoting sustainable resource utilization. This study comprehensively investigates the feasibility of using waste coal water as a partial and complete substitute for mixing clean water in concrete production instead of traditionally discharging into nature. The experimental program was designed using three concrete batches including 0 %, 50 %, and 100 % coal wastewater. After 28 days of curing, the mechanical properties of the cube specimens were evaluated through compressive strength tests. Additionally, reinforced concrete (RC) beams produced with the same batch ratios were tested under flexural bending to assess their structural performance, crack propagation, and failure mechanism. Notably, the 100 % water replacement exhibited %17 superior load capacity, 272.26 kN, while extending the displacement at failure from 2.16 mm to 4.75 mm over control specimen. Three-dimensional finite element models and analytical calculations incorporating material nonlinearities were developed to reproduce the ultimate load capacities and failure observations where the calculated errors within %5 and 30 %, respectively. Microstructural analyses using scanning electron microscopy (SEM) were also conducted to examine the influence of coal wastewater on hydration reactions, chemical bonding, and pore structure development. The proposed approach offers significant environmental benefits by reducing freshwater consumption and promoting the recycling of industrial waste, thereby contributing to sustainable and resilient concrete production in structural applications.