Abstract Natural phosphate rock reserves are limited to few geographical regions around the world requiring supply chains that are prone for geopolitical and natural disaster risks. Considering phosphorus (P) as a critical mineral, a strategic commodity P reserve from recycled P was explored at an urban scale representative of a large metropolitan area. Water resource recovery facilities (wastewater treatment facilities) are the ideal P sink where P can be recovered from wastewater. Using data collected in a metropolitan area, a Triple Bottom Line (TBL) sustainability analysis considering economic, social, and environmental impacts and benefits was conducted in comparing P recovery approaches including recovered as biosolids for land application; as fertilizers for immediate use; and recovered from sewage sludge ash (SSA) as P reserves. Evaluation criteria selected for the TBL analysis are: Economic category includes capital expenditures (CapEx) and operating expenses (OpEx); Social category includes public health and sustainable P supply; and Environmental category includes future regulations, air quality impacts, water quality impacts, and greenhouse gas (GHG) emissions. Recovering P from SSA of the study area would require a capital investment of approximately 760 M USGS (2019) which is the most expensive due to construction of a new centralized facility. However, recovery of P from SSA showed the best TBL benefits among the three scenarios. The principal reasons are: a sustainable P supply in the future from recovered P as well as a safer final sludge disposal option compared with land application option. The annual OpEx for Scenario 3 was estimated at 62 M USGS (2019) which is also more attractive than the other scenarios due to reduction in sludge truck hauling distance and improved efficiency by centralizing the operation. From a sustainable P supply and public health perspective, the benefits of storing recovered P as reserves far outweighs the benefits of land application or when recovered as fertilizers for immediate use. This research presents a novel approach to secure future P supply by centralization of P recovery from SSA. Researchers can follow the approach and conduct analyses using evaluation criteria that are most applicable to their own regions.