**Abstract**

Heavy metals are major contaminants in groundwater, and they have potentials for toxicity even at low concentrations with health hazards. This led to the determination of heavy metal concentrations and evaluation of HMPI and MI of groundwater sources in Keffi and Karu to ascertain the suitability for domestic usage. Heavy metals, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn, were determined using AAS. The results obtained showed that Cd, Cr and Pb had mean concentrations higher than the SON recommended limit. Statistical analyses at *p* < 0.05 showed that there were no significant differences between heavy metal contents in water from boreholes and wells in Keffi and Karu. HMPI were 77.33 and 92.08 for borehole and hand dug well water respectively in Keffi and 105.27 and 127.41 for borehole and hand dug well water respectively in Karu. The values from Keffi are lower than the critical value of 100, while those of Karu are slightly higher. MI for borehole and hand dug well waters was 0.564 and 0.606 respectively in Keffi and for Karu, the values were 0.634 and 0.723 respectively and are all less than 1. These suggest that the water sources are not affected with heavy metal pollution when compared to the water quality classification scheme adopted.

**Keywords:** heavy metals, water, contamination, pollution, metal index
