Background: Access to safe drinking water, sanitation and handwashing facilities is unequal within Nigeria, but few studies compare local government areas (LGAs) with different levels of WASH compliance. We compared these services between compliant and non-compliant LGAs in Rivers State. Methods: A comparative cross-sectional study was conducted in four LGAs: Port Harcourt and Akuku-Toru (compliant) and Okrika and Emohua (non-compliant). In total, 422 adults were selected by multi-stage sampling, with a Cochran-based sample allocated in proportion to population, and interviewed using a structured questionnaire. Data were analysed with SPSS version 26 using frequencies, percentages and Pearson’s chi-square test (p < 0.05). Results: Access to safe drinking water was reported by 94.9% of respondents in Port Harcourt, 93.9% in Akuku-Toru, 60.7% in Okrika and 50.0% in Emohua. Access to improved sanitation was 91.0%, 90.9%, 53.6% and 46.2%, and handwashing facilities with soap and water in public places were reported by 89.6%, 90.9%, 42.9% and 34.6%, respectively. Compliant LGAs had significantly higher access to safe drinking water (94.8% vs 55.6%), improved sanitation (91.0% vs 50.0%) and handwashing facilities (89.7% vs 38.9%) than non-compliant LGAs (all p < 0.001). Conclusion: Access to all three services was substantially better in compliant LGAs, with the widest gap in handwashing facilities. Closing these gaps in Okrika, Emohua and similar LGAs will require strengthening local WASH institutions as well as infrastructure.