The Massachusetts Water Resources Authority (MWRA) supplies water to 2.5 million people in Eastern Massachusetts. Currently, the surface water supply is unfiltered. To determine the best way to comply with the Safe Drinking Water Act Amendments (SDWA), the MWRA initiated watershed protection and pilot treatment studies. This paper summarizes the major findings of the pilot treatment study. In particular, it compares the performance of dissolved air flotation with that of inline filtration, direct filtration, and contact adsorption clarification. Each process was evaluated for turbidity removal, filter production, particle reduction, disinfection byproducts, effect of ozonation, and coagulants. As a result of the piloting, a treatment process train consisting of dissolved air flotation, ozone, biological filtration, and chloramination was recommended.