The availability of clean water is one of the most significant challenges facing the world today. Polymer membranes are one of the most promising solutions to the water-scarcity problem. I lead a project that focuses primarily on thin film composite membranes, where the selective layer that separates water from dissolved ions is only 10s to a few 100s nm thick. Probing the structure and dynamics of such thin layers is a significant measurement challenge. Providing industry with the measurement tools and proficiency will enable scientists and engineers to design more selective and energy-efficient membranes.