ObjectiveTo explore the differences between shanghai water quality standards for drinking water （DB31/T 1091-2018） and domestic and foreign water quality standards， and to compare the improvement of water quality before and after the implementation of DB31/T 1091-2018.

MethodsTo compare shanghai water quality standard for drinking water with domestic and foreign standards in terms of index number， indicators of disinfectants and their by-products， increased indicators， and revised indicators， and the key water quality indicators before and after the standard implementation in Pudong New Area of Shanghai were investigated.

ResultsThe number of new standard increased from one hundred and six to one hundred and eleven. Among them， the number of conventional indicators increased from forty-two to forty-nine， while the number of unconventional indicators decreased from sixty-four to sixty-two，seven new conventional indicators were added， and the limit value of seventeen conventional indicators was revised and so on. By analyzing water quality monitoring data of New standard before implementation （2017） and after implementation （2019） at water plants of Pudong New Area of Shanghai ， it is found that the total number of bacteria （Z=-2.772，P<0.01）， and carbon tetrachloride （Z=-5.570，P<0.01），trichloromethane （Z=-5.685，P<0.01）， turbidity （Z=-4.168，P<0.01）， total dissolved solids （Z=-7.061，P<0.01）， and total hardness （Z=-2.338，P<0.05）， oxygen consumption （Z=-2.580，P<0.05）， anion synthetic detergent （Z=-2.162，P<0.05）， total chlorine （Z=-2.826，P<0.01）， there were significant statistical differences between the two groups， while there were no statistical differences between the other indicators.

ConclusionThe new standard refers to the domestic and foreign drinking water standards， tends to the high and strict requirements， and pushes the improvement water quality of the centralized water supply units， which need to carry out in-depth treatment process transformation， in order to further optimize the water quality.