This study evaluated the water quality status of boreholes around a landfill site in Port Harcourt, Nigeria. Borehole water samples were taken around the landfill site and standard analytical methods were employed. The results indicated that Electrical Conductivity (EC), TDS, Fe, CO2, and NH3 have high concentrations exceeding DPR guideline. EC and TDS with values ranging from 39.5 μS/cm to 102.4 μS/cm and 110mg/l to 1355 mg/l indicated high concentrations of dissolved organic contents on the landfill. NH3 concentration were also high with values ranging from 4.57 mg/l to 9.61 mg/l. Salinity concentration ranges from 180.50 mg/l to 481.37 mg/l and Chloride with concentration values of (300 mg/l and 266.67 mg/l) are below DPR guideline, indicating low salt content in the water. COD has a high value of (117.39 mg/l). Carbondioxide (CO2), with high values range between 2420.09 ppm to 6634 ppm. This is because of high amount of organic and inorganic matters released from the landfill and can be toxic to human's health. Ammonia (NH3) with values of (3.26 mg/l), (2.95 mg/l), (9.61 mg/l), (4.57 mg/l), (9.61 mg/l) and (8.24 mg/l), respectively is above DPR limit, indicating that the landfill is characterized by biogas. This is due to an oxygen deficit in decomposition of organic matters. Regular monitoring of groundwater quality in the area is recommended.