As the EPA has promulgated the final maximum contaminant levels (MCLs) and hazard index (HI) for PFAS contaminants in 2024, many utilities are facing decisions on how to address compliance within the anticipated deadlines. With the speed at which these new final regulations are approaching, many utilities are considering how to quickly collect site-specific performance data to make decisions on what treatment process(es) to implement for PFAS. Pilot testing is a critical part of the planning and project development process for reliable and cost-effective PFAS treatment, including consideration of site-specific operational and water quality parameters. This includes understanding what technologies are most applicable based on the specific PFAS compounds present, the key water quality constituents that affect most PFAS treatment technologies, such as iron, manganese, and TOC, and location for PFAS treatment in the existing treatment train. This presentation will discuss critical planning, design, and implementation issues specific to PFAS treatment pilot testing, including the use of Rapid Small Scale Column Testing (RSSCT) as a tool for enhancing the speed and efficiency of pilot testing for a given water supply. Two case studies will be presented of projects that performed pilot testing: one on a groundwater supply, and the second on a surface water supply. The case studies will highlight critical questions each pilot was designed to answer. Issues such as pilot duration, number of processes/technologies tested, sampling, and operational needs will be reviewed. Attendees will gain an understanding of the questions to consider, specific to their water system, and how to implement an effective, timely pilot that will successfully translate to implementation of a full-scale treatment system for PFAS that meets all treatment goals without any unintended consequences.