Recently, as part of an on-going American Water Works Association Research Foundation project, a two-page survey (i.e., SUVA survey) was conducted among drinking water practitioners and researchers (Karanfil et al., 2002). The survey objectives were to determine current practices for measuring dissolved organic carbon (DOC) and ultraviolet (UV) absorbance, thus their implications on specific ultraviolet absorbance (SUVA) determination, and to compare them with the procedures specified in Standard Methods and the US Environmental Protection Agency's Enhanced Coagulation Guidance Manual. One hundred thirty-eight (138) responses, including 12 commercial and government laboratories, 21 university researchers and 105 water utilities, were received from 34 states in the U.S. and three other countries. Survey results indicated that filter selection (pore size and type), filter cleaning, and sample filtration are particular areas where notable differences existed among respondents. Therefore, the present study was undertaken to examine the impacts of filter selection, cleaning and sample filtration on DOC and UV254 measurements. Three factors can significantly impact DOC and UV254 measurement results, and thus SUVA254 determinations: leaching of organic and UV254 absorbing components from filters; adsorption of dissolved and colloidal organic matter by filters; and, fouling of filter membrane surfaces by the buildup of particulate matter present in raw waters. This paper summarizes the major findings from a systematic investigation of the first two factors. A detailed summary of the findings from this work has recently been published in an article in the Journal of American Water Works Association (Karanfil et al., 2003) and can also be found in other documents currently being prepared (Karanfil et al., 2003; Erdogan, 2003). Includes 8 references, tables, figures.