In order to understand and improve drinking water treatment process operations, many techniques have been established to characterize natural organic matter (NOM). Resin fractionation is the most widely used technique to isolate NOM based on its hydrophobicity and hydrophilicity, these can be used to determine the treatability of NOM, however, it is also recognized as a time consuming technique. This paper describes the use of reverse phase high performance liquid chromatography (RPHPLC) as a rapid assessment of the hydrophobicity/hydrophilicity of NOM. The reduction of total RPHPLC peak area correlated well with dissolved organic carbon (DOC) and UV absorbance at 254 nm (UV254) removal efficiency. After resolving the RPHPLC profile using a peak fitting technique, the ratio between hydrophobic and hydrophilic peak area can be used to quantify the treatability of NOM (particularly DOC removal). Further statistical analysis grouped the resolved peaks into three groups (two groups of hydrophilic and one group of hydrophobic) and established an expression to link peak area with UV254 and DOC removal. The characterization results were further compared by the traditional resin fractionation technique using DAX-8 and XAD-4 resins (combined). The results confirmed that despite the definition that hydrophobic and hydrophilic components measured by both methods could be different, both methods confirm that the hydrophilic fraction was recalcitrant after coagulation and is of small molecular weight. (C) 2012 Elsevier B.V. All rights reserved.