This research attempted to identify water quality and water treatment parameters that can potentially influence the creation of biodegradable organic matter (BOM) and aldehydes, and derive correlations of BOM (estimated by measuring assimilable organic carbon [AOC] and biodegradable dissolved organic carbon [BDOC] and aldehydes, with ozone dosage, and water quality variables, through multiple regression analysis. Aldehyde formation was influenced by ozone dosage, alkalinity, nonhumic fraction of DOC, chlorophyll a, and DOC. Ozonated water BDOC level was a function of raw water BDOC concentration and ozone dosage, whereas AOC concentration in ozonated water was related to raw water AOC level, alkalinity, and ozone dosage. Multiple regression analysis showed good correlations of AOC, BDOC, and aldehydes with the variables listed. Includes 39 references, tables, figures.