Since 2014, The United States Air Force Civil Engineering Center (AFCEC) has been conducting on-going response activities to remediate groundwater impacted by poly- and perfluoroalkyl substances (PFAS) at the former Pease Air Force Base in Portsmouth, New Hampshire. AFCEC’s response included the installation and operation of a full-scale regenerable ion exchange (IX) resin system to remediate groundwater in the source area impacted by years of firefighting training activities. The resin system was selected based on the results of a comprehensive pilot test that evaluated and compared the effectiveness of multiple treatment technologies. In parallel, PFAS contamination was detected at elevated levels in the City of Portsmouth (City) public water supply in 2014. The Haven water supply well, located on the Pease Tradeport, was immediately shut down by the City. The source of PFAS contamination was traced back to the historical use of firefighting foam at the nearby Pease Air Force Base. A SORBIX RePURE regenerable resin system was installed to meet the primary source area remediation objective of treating the groundwater PFOS+PFOA concentration to below the 0.07 µg/l Health Advisory Level. Design, installation and startup of the full-scale SORBIX system was completed from fall 2017 to spring 2018. Based on the successful application of ion exchange resin at the former fire training area, The City decided to run a pilot test to evaluate the effectiveness of single-use IX resin versus bituminous Granular Activated Carbon (GAC). The pilot system was designed and fabricated to pump directly from the Haven Well and facilitated comparison of the two technologies at four different empty bed contact times (EBCTs); 2.5, 5, 7.5 and 10 minutes. The full-scale source area regenerable resin PFAS remediation system has successfully treated groundwater with a total influent average PFAS concentration of 48 µg/l since April 2018. The treated water quality from the SORBIX RePURE resin system has been consistently non-detect for PFOS+PFOA compounds, readily achieving compliance with the 0.07 µg/l HAL target. Operational modifications have been made to address and correct minor challenges with the resin regeneration system, and regenerant recovery and related waste minimization processes have proven highly effective. No PFAS waste has needed to be hauled off site after more than 16 months of operation. The IX resin results were similarly successful in the City’s public water supply pilot test. The influent total PFAS concentration averaged 3.5 µg/l over the course of the year-long evaluation. The IX resin substantially outperformed the GAC on all 12 PFAS that were present at detectable levels. The GAC column was operated until PFOA+PFOS breakthrough reached 0.07 µg/l at the 10-minute EBCT. This occurred at approximately 13,000 bed volumes (BVs), roughly 2.5 months into the test. By contrast, the IX resin effluent from the shortest (2.5-minute) EBCT column remained well below the 0.07 µg/l HAL, even after treating more than 171,000 BVs over a 12-month period. Based on the results of the comparative pilot test, the City selected IX resin for full-scale implementation to remove PFAS from the Haven water supply. The City’s engineer, Weston & Sampson, led the evaluation and attributed the selection of IX resin to the smaller footprint and lower capital and O&M costs associated with the technology. The full-scale system is scheduled to commence operation in 2020.