This paper and associated conference presentation discuss the multi-faceted function of NF/RO in potable reuse treatment and the influence of this diverse functionality on the cost-benefit analysis between the performance enhancement and economic efficiency strategies for treatment system design. The critical role of NF/RO integrity testing in such an analysis is also discussed, highlighting the regulatory gap between demonstrated capability and awarded pathogen removal credit. Applicable data and examples from the recent nine-month El Paso Water (EPW) direct potable reuse (DPR) pilot is provided, as applicable, to serve at practical context from an ongoing project.