Levels of lead and iron in well-water of seven selected local government area within Ibadan metropolis were quantified using atomic absorption spectrophotometer (AAS, Buck 200). The toxicity of lead was also tested in albino rats for a period of two weeks (14-day exposure) using enzyme assay where the activities of the following enzymes Alanine-amino transferase (ALT), Aspartate-amino transferase (AST), Alkaline phosphatase (ALP) and Gamma-glutamate transferase (γ-GT) were determined against lead induction. The laboratory experiment was divided into two sets I and II where set I was for serum and set II for liver fraction respectively. Results obtained from this research showed high significant lead levels (P<0.05) in well-water within Ibadan metropolis compared to (WHO) permissible lead levels (0.01-0.02p.p.m) in drinking water as lead levels found ranged between (0.05- 0.15p.p.m). Besides, significant (P<0.05) levels of iron were equally obtained from same water samples collected. However, the results from this assay showed that lead was toxic and foreign to the test animals, as remarkable degree of enzyme induction was observed which consequently leads to hyperactivity of the enzymes.