Groundwater vulnerability to leachate contamination is a significant public health concern, particularly in developing countries where non-engineered landfill sites are common. These sites pose a huge risk of contaminating groundwater resources used for drinking. The study employed a comparative case study research design utilising the GOD and RTt vulnerability assessment methods to evaluate the risk of leachate contamination at the Botshabelo non-engineered landfill site. Field data, including depth to groundwater and nitrate concentration, were collected using a Solinst 101 water level meter, and groundwater samples were analysed at the University of the Free State Institute for Groundwater Studies. Results showed that the GOD method indicated a very low vulnerability with an index of 0.08, while the RTt method suggested a moderate vulnerability with an index of 53. Validation using nitrate concentration yielded a mean of 0.33 mg/ℓ, confirming very low contamination levels which aligned closely with the GOD model. The rise in values observed in RTt was attributed to the shallow depth of groundwater and slope sensitivity, while the relatively flat trend in GOD findings was linked to the dominance of confining lithological layers. The findings highlight the importance of selecting assessment methods that are well-adapted to local conditions such as soil type, lithology, precipitation, and slope. Although the study indicated low contamination risk, ongoing monitoring and additional water quality testing are recommended to ensure the continued safety of groundwater for consumption.