AbstractThe raw waters from the Yellow River and the Danjiangkou Reservoir are the two most important sources of water in the water-receiving areas of the south-to-north water diversion project (SNWDP). This paper compared the constitution of dissolved organic matter (DOM) in the two waters based on XAD resins isolation, ultrafiltration fractionation, and the disinfection by-product formation potential of each fraction. The dissolved organic carbon (DOC), UV254, trihalomethanes, and nitrogenous disinfection by-product (N-DBP) formation potential of the raw water from the Yellow River were higher than those from the Danjiangkou Reservoir. The molecular weight (MW) < 1 kDa fraction contained the most DOM and dominated the major THM formation potential (THMFP) and N-DBP formation potential (N-DBPFP) in both waters. The hydrophilic fraction possessed the highest proportion in the Yellow River water, while the transphilic fraction was predominant in the Danjiangkou Reservoir water. In both waters, the hydropho...