Access to safe and clean water is a major challenge in many rural communities of Abia State, Nigeria. Due to the absence of adequate water treatment facilities, residents in these areas depend largely on untreated surface water from rivers, streams, and ponds for domestic, agricultural, and sometimes industrial purposes. This study investigates the environmental effects of untreated surface water in selected rural areas of Abia State, with emphasis on its physical, chemical, and microbiological qualities, and their implications for public health and the ecosystem. Field sampling and laboratory analyses were conducted on multiple surface water sources in rural communities. The results reveal that these waters contain significant levels of turbidity, suspended solids, and colouration exceeding World Health Organization (WHO) permissible limits. Chemical analyses indicated the presence of undesirable mineral concentrations, including high nitrate and phosphate levels from agricultural runoff, and traces of heavy metals such as lead and cadmium. Microbiological tests confirmed the presence of Escherichia coli, total coliforms, and other pathogenic organisms, indicating faecal contamination. These findings suggest that the continued use of untreated surface water poses a dual threat: increased risk of waterborne diseases such as cholera and typhoid, and environmental degradation including eutrophication, biodiversity loss, and soil contamination. The study concludes that urgent interventions—including community-level treatment systems, stricter water protection policies, and sustained public health education—are necessary to mitigate the negative impacts and promote sustainable water management in rural Abia State.