Abstract: Objective:To study the heavy metal concentrations, changing trends and influencing factors in drinking water from 2015 to 2020 in Nanning City.Methods:The detection values of 11 heavy metals arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), mercury (Hg), selenium (Se), aluminum (Al), iron (Fe), manganese(Mn), copper (Cu) and zinc (Zn) in 6, 983 drinking water samples from urban and rural areas in Nanning City from 2015 to 2020 were collected.The exposure levels of heavy metals and their changing trends were analyzed.Results:Among the 11 heavy metals in drinking water in Nanning, except Cd, Cr, Hg and Cu, the concentrations of other seven metals exceeded the national standards, and the top four metals were Mn, Zn, Fe and Al, with the over-standard rates of 1.82%, 1.76%, 1.26%and 0.93%, respectively.The total over-standard rates of heavy metals showed a descending trend year by year, from 9.87% in 2015 to 3.22% in 2020.The concentrations of Mn, Fe, Hg and Al presented no significant changes in different years.The pollution indexes of the 3 heavy metals Hg, Al and Zn in the wet season were higher than those in the dry season.Water treatment processes such as precipitation filtration and disinfection could affect the exposure levels of heavy metals.The concentration of Se decreased by precipitation filtration.Both precipitation filtration and disinfection could reduce the over-standard rate of Mn, while the pollution level of Al increased by precipitation filtration.Conclusion:The concentrations and pollution levels of heavy metals in the drinking water in Nanning show a descending trend year by year, and industrial, agricultural and domestic pollution are gradually controlled.Special attention should be paid to the heavy metals with high natural background in the wet season and great influence by external factors and it is suggested to strengthen the technological innovation in water treatment to avoid bringing in additional pollutants.