USEPA regulations of Disinfection By-Products (DBPs) require water suppliers to be in compliance with maximum contaminant levels set by the agency’s Stage 2 DBP Rule. Controlling watershed sources of byproduct precursors are of interest to water suppliers. By-product formation potential and DOC (dissolved organic carbon) character were evaluated at eight sites on four dates (n=32). All sites are within Springfield Water and Sewer Commission’s Cobble Mountain Reservoir watershed (Blandford and Granville, Ma). The goal was to investigate how DBPFP (DBP formation potential) changes in relation to landscape driven changes in DOC chemical characteristics. Analysis was performed on raw water samples using UV-Visible Spectroscopy. 1H Nuclear Magnetic Resonance Spectroscopy (NMR), and Fourier Transform Infrared Spectroscopy (FT-IR) were performed on solid phase extractable (SPE-C18) hydrophobic DOC. Changes in DBPFP are related to landscape changes in hydrophobic DOC characteristics. On three of the four sample dates (n=24) DBPFP was positively correlated to the E2:E3 ratio (R2=.37), SUVA (R2=.72), percent aromatic resonance (R2=.60), and percent carbohydrate resonance (R2=.44). DBPFP on three sample dates (n=24) was negatively correlated to percent aliphatic resonance (R2=.48). DOC aromaticity, SUVA and specific formation potential were lowest in headwater streams and increased with distance downstream. Substantial reductions in DOC concentration are seen upon reservoir export. For most parameters headwater in-stream variability was greater than inter-stream variability. Differences among headwater streams of different forest type are not distinguishable in our small sample size (n=12). Only slight differences in specific formation potential were observed among two different depth samples in Cobble Mountain Reservoir. Our results have implications for watershed management practices in the drinking water supply industry of New England.