The Niger Delta contains extensive surface-water and groundwater resources that support domestic activities, agriculture, fisheries and other livelihoods, but petroleum exploration and production have created persistent environmental pressures. This study assesses environmental management practices, water quality and water-security conditions in four selected oil-producing communities: Bodo in Rivers State, Otuabagi in Bayelsa State, Ogidigben in Delta State and Ibeno in Akwa Ibom State. A mixed-methods design involving water-quality assessment and questionnaire administration was adopted. A model dataset comprising 16 water samples and 200 questionnaire respondents was developed for statistical demonstration. Physicochemical parameters, including pH, electrical conductivity, nitrate, total petroleum hydrocarbons (TPH) and lead (Pb), were evaluated. The illustrative results showed mean TPH concentrations of 1,050, 690, 400 and 895 µg/L for Bodo, Otuabagi, Ogidigben and Ibeno, respectively. Mean lead concentrations were 50.0, 35.5, 20.0 and 52.0 µg/L, respectively. One-way ANOVA produced F = 26.48 and p = 0.004, indicating statistically significant differences among the illustrative community TPH values. Questionnaire responses indicated concerns about groundwater dependence, pollution and remediation effectiveness. The study demonstrates the importance of integrated pollution prevention, environmental monitoring, remediation, community participation and sustainable water-resource management in improving water security in the Niger Delta.