With clean water becoming increasingly scarce, safe and effective treatment methods are essential. Chemical disinfectants like Monoethanolamine (MEA) and Monopropylamine (MPA) are widely used due to their cost-effectiveness, but their health risks remain unclear. To investigate the sub-chronic oral toxicity of two commercially used antiscalants to assess their potential health risks and to develop a safer and more sustainable water treatment methods, we conducted a 28-day study on 70 rats to assess their sub-chronic oral toxicity. Blood analysis revealed significant increases in WBC, MCV, MCH, PLT, and PCT levels, along with a notable rise in ALP (p < 0.05). Histopathological examination showed severe liver, heart, and lung damage, including necrosis, inflammatory cell accumulation, and tissue degeneration. These findings suggest that MEA and MPA pose serious health risks, raising concerns about their widespread use in water treatment. Given their potential impact on human health and the environment, it is crucial to reassess their safety and explore alternative disinfectants. Ensuring the long-term safety of water treatment methods is vital for public health and environmental sustainability, making further research and regulatory evaluation necessary.