This study was conducted to evaluate the source and fate of nitrate in surface and ground water.rnThe characterization of nitrate (NO3) in major rivers and aquifers of the Addis Ababa area wererninvestigated by Isotopic and geochemical conditions. And an overall understanding on thernsources and fate of NO3 in the surface water and the groundwater was obtained. The NO3rnconcentrations in both surface and ground water were very low and no samples exceed the WHOrnstandards while concentration of other nutrients such as PO4-, Cl- and NH4+ were higher onrnsurface waters.rnThe Redox condition estimated based on measurements of redox parameters of Eh, The analysisrnrevealed that most of the surface water had anaerobic condition and presence of strong reducingrnconditions in the surface water and the recharge ground water. The anoxic condition is providedrnby high organic matter content in the surface water and result depletion of oxygenâ€™s.rnHere the Î´2H_H2O and 8Î´18O_H2O result shows that the source of ground water in the city isrnheavy rain fall of different regime and shallow ground water recharge hypostasis is from rain fall.rnThe recharge of surface water is from dam reservoirs and mixing between tap waters and groundrnwaters. This study brings some clear evidences that unwanted anthropogenic nutrients can bernreleased in both surface waters and shallow groundwater from rapidly growing cities. In addition,rnthese polluted waters can create a serious treat for the downstream populations, with the need tornimplement expensive tertiary treatment plants to remove nitrate.rnThe chemical data shows that the concentrations of nutrients other than nitrate were higher andrnshows the pollution of surface waters but low nitrate. From the correlation of nitrate speciousrnwith other geochemical parameters reveals that the source for nitrate and other nutrients werernthe same such as wastes from manure, septic systems, fertilizer and industries.