Assessing water safety and treatment feasibility in Nigeria's public boreholes: toward SDG 6.1 compliance

ABSTRACT Nigeria's public boreholes, vital for water access, often fail safety standards, jeopardising SDG 6.1's goal of universal access to safe drinking water. This study integrates quantitative contamination profiling, qualitative barrier analysis, and pilot treatment trials to evaluate borehole water quality, assess treatment efficacy, and examine the suitability of the Nigerian Industrial Standard (NIS) 554:2015 in low-resource settings. Analysis of 36 borehole samples across six states found 80.6% non-compliant, with 38.9% showing both microbial and geogenic contamination. Total Plate Count was the most reliable microbial screening trigger (sensitivity 0.92, negative predictive value 0.95, area under the ROC curve 0.88), whereas turbidity was a weak microbial indicator. Conductivity-TDS and hardness-TDS associations were robust, supporting electrical conductivity as a low-cost geogenic proxy. The pilot treatment trials achieved health-critical compliance at two Smart Water Kiosks, providing insights into treatment barriers, operational requirements, and scalability in resource-constrained environments. A multi-criteria decision analysis motivates phased regulatory compliance as a direction for further study, balancing public health priorities with financial feasibility. The study offers actionable recommendations to align standards, infrastructure design, and financing mechanisms to enhance safe water delivery in Nigeria and similar contexts.