The study aims to conduct a study of variability of heavy metals in Kanzenze River of Upper Akagera Catchment, Rwanda for sustainable irrigation in Rwanda. Findings showed that two categories of heavy metals were identified: Category I (heavy with permissible limits) and Category II (heavy metals out of permissible limits) as prescribed by FAO (Food and Agriculture Organization) guidelines for irrigation. Based on FAO guidelines for irrigation, on average, the study findings revealed that available heavy metals present in Kanzenze water river were Calcium (Ca) [22.524 mg. L-1] which falls out permissible limits of 0-20 mg. L-1; Magnesium (Mg) is out of range with [23.006 mg. L-1]. Potassium ( K) [19.290 mg. L-1] is out of range as per FAO guidelines, for irrigation, [K] should be in range of 0-2 mg. L-1; Copper (Cu) [0.746 mg. L-1] is too high compared to FAO guidelines, for irrigation, recommended maximum copper content should not exceed 0.2 mg. L-1; Manganese (Mn) [156.534 mg. L-1] is very high compared to FAO guidelines, for irrigation, recommended maximum manganese content should not exceed 0.20 mg. L-1; Cadmium (Cd) (0.744 mg. L-1) indicated very high concentration as per FAO guidelines, for irrigation, recommended maximum Cadmium content should not exceed 0.01 mg. L-1 and Chromium (Cr) (3.202 mg. L-1) is out of permissible range as per FAO guidelines, for irrigation, recommended maximum chromium content should not exceed 0.1 mg. L-1. Hence there is a need take care of water treatment for irrigation. Second category are heavy metals having concentration falling in permissible limits prescribed by FAO guidelines including Sodium (Na) [7.654 mg. L-1] is in permissible limits of 0-40 mg. L-1 as per FAO guidelines for irrigation activities; Zinc (Zn) [0.863 mg. L-1] is in range as per FAO guidelines, for irrigation, recommended maximum Zinc content should not exceed 2.0 mg. L-1; Lead (Pb) [1.216 mg. L-1] falls in permissible limits as per FAO guidelines, for irrigation, recommended maximum lead content should not exceed 5.0 ppm respectively. Based on FAO sequence of heavy metals in descending order, Kanzenze river has heavy metals ordered as Mn>Mg>Ca>K>Na>Cr>Pb>Zn>Cu>Cd in descending order with respective concentration 156.534 ppm to 0.744 ppm for Manganese (Mn) to Cadmium (Cd)

Keywords: Water Quality, Heavy metals, Principal Component Analysis