Groundwater serves as a vital source of potable water in rural and peri-urban communities across Nigeria, yet its quality is increasingly compromised by anthropogenic activities. This study investigates the synergistic effects of industrial pollutants on groundwater quality in Umuabulu, Igbo-Etche, Rivers State, within the hydrocarbon-rich Niger Delta. Five geospatially distinct sites were sampled; physicochemical, heavy metal and organic contaminant concentrations were assessed in comparison with World Health Organisation (WHO) standards. Results revealed progressive deterioration in water quality along pollution gradients. Physicochemical parameters, including electrical conductivity (1240 ± 115 µS/cm), total dissolved solids (622 ± 55 mg/L), turbidity (6.8 ± 0.9 NTU), biochemical oxygen demand (4.6 ± 0.6 mg/L) and chemical oxygen demand (14.6 ± 1.3 mg/L), exceeded WHO permissible limits in multiple sites. Heavy metals such as lead (31.2 ± 2.6 µg/L), cadmium (6.2 ± 0.6 µg/L), chromium (78.6 ± 6.8 µg/L) and iron (598 ± 52 µg/L) were also above guideline values, alongside elevated organic contaminants including total petroleum hydrocarbons and volatile organic compounds. The observed interactions between heavy metals and organic pollutants intensified aquifer vulnerability, reduced dissolved oxygen levels and increased risks of chronic toxicological exposure. These findings highlight significant public health and ecological risks in Umuabulu, underscoring the urgent need for stricter regulatory enforcement, improved waste management, and sustainable groundwater monitoring strategies in oil-impacted communities.