Compliance of Rural Water Quality to Global Target on SDG 6: Case Study of Osun State, Nigeria

Access to safe and clean water is essential for sustainable development, particularly in rural areas where infrastructural deficits and sanitation challenges are pronounced. This study evaluated groundwater quality in 32 rural communities across 10 local government areas (LGAs) of Osun State, Nigeria, in relation to Sustainable Development Goal (SDG) Target 6.3, which aims to improve water quality by reducing pollution and eliminating hazardous discharges. Water samples were analysed for physico-chemical parameters-pH, temperature, total alkalinity, total dissolved solids (TDS), electrical conductivity (EC), total hardness, nitrates, phosphates, sulphates, chlorides, and turbidity-and microbiological indicators, including total coliforms and Escherichia coli (E. coli). Results indicate that most physico-chemical parameters complied with World Health Organization (WHO) and Nigerian standards, suggesting minimal chemical degradation of groundwater. In contrast, widespread microbiological contamination was observed, with elevated coliform counts and E. coli presence in 14 communities, identifying faecal contamination as the primary factor undermining SDG 6.3 compliance. Water Quality Index (WQI) analysis further revealed substantial spatial variation: several villages scored "excellent" or "good," whereas others, including Owu-Ile, Masifa, and Alaasan, were classified as "very poor" or "unsuitable" for drinking. Hotspots of microbial non-compliance were concentrated in Ejigbo and Ede North LGAs, while temperature and minor alkalinity deviations were observed in select communities.The findings highlight that failures in rural water quality are predominantly driven by inadequate sanitation and hygiene practices rather than chemical contamination. Achieving SDG 6.3 in Osun State therefore requires targeted interventions, including strengthened rural sanitation infrastructure, routine microbial monitoring, community-based water governance, and spatially prioritised resource allocation. The integration of WQI provides a practical tool for synthesising multi-parameter water quality data, enabling policymakers to identify high-risk communities and design evidence-based strategies for sustainable rural water management in Nigeria.