Reverse osmosis and nanofiltration are highly adopted, growing technologies that are used to remove salts and other small molecules in water treatment. Both of these technologies primarily use cross-linked polyamide membranes to achieve the desired separation. Many novel nanoporous materials are being developed as alternatives or complements to polyamides, including graphene, graphene oxide, block copolymers, liquid crystals, aquaporins, and other biologically inspired molecular channels. This article evaluates each of these technologies by (i) reviewing the current progress in each area, (ii) identifying key needs for immediate research, and (iii) evaluating considerations for commercial development. The economic benefits of these technologies in reverse osmosis applications are further reviewed to help frame the expected commercial value proposition.