The design approach of pressure or vacuum type membrane systems in a water treatment plant (WTP) is different than conventional WTP design due to the general physical principles of each process. For example, the hydraulic grade line, as well other key design parameters, can change depending on whether a pressure or vacuum type system is selected. This poses a problem for the design engineer as developing contract documents for both alternatives would not be cost effective or the best option to minimize the "risk" of confusion during the bidding process. To circumvent this problem, it is necessary to implement a membrane procurement process prior to the development of detailed design documents for the proposed WTP. This procurement process consists of three key phases which include prequalification, piloting, and submittal of a detailed proposal for the full-scale design of the membrane filtration WTP. Proposals from the membrane suppliers are evaluated based on the previously defined selection criteria, which includes both qualitative and quantitative criteria. Some examples of qualitative criteria includes piloting performance (i.e. consistency of finished water product, membrane integrity test procedures, etc.), and proven full-scale performance (large municipal plants in service, etc.), while the quantitative criteria consists of total capital cost of membrane system and total present worth cost over the life cycle of the membrane system. By using this process, it balances out the cost with the tangible qualitative benefits that one membrane system may have over another. This paper describes the membrane procurement process used in the design of a membrane filtration water treatment plant. Includes tables, figures.