Water bodies have been severely degraded in recent years due to the indiscriminate use of agro-allied chemicals. The study assesses the agro-allied chemical pollution on the surface water quality in River Lamurde and Mayo Gwoi. Water samples were collected from twenty-one (21) sample locations along the River Lamurde and Mayo-Gwoi to determine the seasonal variation during the wet and dry seasons through field determination of water quality and laboratory-based analysis at Taraba State Rural Water Supply and Sanitation Corporation (TAWASCO) Jalingo laboratory. The water quality parameters that were subjected to test include: Calcium (Ca), Nitrate (NO₃^-), Zinc (Zn), Nitrite (NO₂^-), Chromium (Cr), Phosphate (PO₄^3-), Iron (Fe), Sulfate (SO₄) and Copper (Cu), The data acquired from the laboratory test was subjected to the analysis of variance (ANOVA). The result of the laboratory analysis shows that the concentration of copper during the dry season and Sulfate during the wet season in river Lamurde and Mayo Gwoi falls within the permissible limits of WHO/NSDWQ while the concentration of Calcium (Ca), Nitrate (NO₃^-), Zinc (Zn), Nitrite (NO₂^-), Chromium (Cr), Phosphate (PO₄^3-) and Iron (Fe) far exceeds the permissible limits of WHO/NSDWQ during the dry and wet season. The findings show that the main causes of the pollution are human activities such as fertilizer application and other agro-allied chemicals around the bank of River Lamurde and Mayo Gwoi. It was recommended that prevention of pollution, treatment of polluted water, safe use of environmentally friendly fertilizers, and other agro-allied chemicals and protection of the ecosystem, among others are desirable actions that will guarantee not only sustainable good quality but also the use of Lamurde and Mayo-Gwoi River water by man.