Ultrafiltration membranes are finding significant applications for providing disinfection in treating pristine waters or as a replacement for filtration within conventional treatment. While ultrafiltration is generally quite effective for pathogen removal, there are limitations, which vary with the particular ultrafiltration membrane process, for removal of color, natural organic matter, and disinfection byproducts (DBP) precursors. This paper presents results of a pilot study comparing immersed and pressurized ultrafiltration processes as a full replacement of conventional clarification and filtration, for DBP and taste and odor (T/O) control. This study was performed at the 10 mgd filtration plant in Wilton, Connecticut, owned by the Second Taxing District Water Department (STDWD) of South Norwalk. The existing plant needs to be upgraded to insure compliance with future regulatory requirements including the Enhanced Surface Water Treatment Rule and Disinfectant-Disinfection Byproducts Rules within the existing plant footprint and at the existing 10 mgd capacity. Piloting was performed over two seasons (winter and summer). Coagulant dosages as high as 35 mg/L alum with and without powdered activated carbon as high as 15 mg/1 were used to achieve natural organic matter (NOM) and DBP precursor removal. Data and comparisons are presented for operational parameters: flux, recovery, and cleaning cycles. Results are presented and compared for turbidity, particle, NOM, DBPFP, SDS-DBPFP with chlorine and chloramine; and removal of 2-methylisoborneol (MIB) and Geosmin. Includes tables, figures.