The Water Filtration Plant (WFP) Improvements Project for the City of Kennewick, Washington was initiated to determine the improvements needed to meet the City's anticipated potable water quality and capacity needs. Submerged low-pressure membranes offer a cost-effective "No Concrete" solution to expanding the WFP, which treats Columbia River water in the summertime to supply peak system demands. This 7.5-million-gallons per-day (mgd) plant includes ozone, rapid mix, flocculation, sedimentation, media filtration, and chlorine disinfection. This paper focuses on the approach and key considerations utilized to implement this unique submerged membrane retrofit project. Although pressure membrane systems can be used to retrofit conventional water plants, submerged membrane technology was better suited for Kennewick's needs. Zenon and USFilter/Memcor are the two major suppliers of submerged membrane systems for drinking water. The system designs are different for each supplier and final design depends on the selected system. Membrane system procurement is critical and establishing a fair and protest-proof bidding environment is essential. The criteria for and test conditions of the membrane pilot testing were developed with this in mind. Careful coordination with each vendor was required to understand the filter building retrofit requirements for each system. Some specific examples of system design parameters that impact the filter building retrofit are: membrane basin depth, overhead crane/hoist capacity and lifting height for the membranes, and locating the permeate pumps adjacent to the membrane tanks. Includes 4 references, tables, figures.