The quality of water body in 20 medium and small reservoirs in Zhuhai was assessed using environmental quality index.The results show that the water quality of medium and small reservoirs in zhuhai is fine.Firstly,water quality in 15 reservoirs reached to the Grade II water quality standards while that in 5 reservoirs attained the Grade I water quality standards among the 20 medium and small reservoirs investigated.Secondly,the key pollutants were total nitrogen.Thirdly,the iron levels in 3 samples were over the limits of surface water and the standards for the daily drinking water.Meanwhile,the sulfide levels in 2 samples were over the standards for the daily drinking water.Finally,all of them need further treatment before serving as drinking water.