The effects of climate change, population growth, and future hydrologic uncertainties necessitate increased water conservation, new water resources, and a shift towards sustainable urban water supply portfolios. Diversifying water portfolios with non-traditional water sources can play a key role. Rooftop harvested rainwater (RHRW), atmospheric and condensate harvesting, stormwater, recycled wastewater and greywater, and desalinated seawater and brackish water are all currently utilized and rapidly emerging non-traditional water sources. This review explores the status and trends around these non-traditional water sources, and reviews approaches and models for prioritizing, predicting, and quantifying metrics of concern. The analysis presented here suggests that understanding the challenges of location specific scenarios, socioeconomic knowledge gaps, water supply technologies, and/or water management structure is the crucial first step in establishing a model or framework approach to provide a strategy for improvement going forward. The findings of this study also suggest that clear policy guidance and onsite maintenance is necessary for variable water quality concerns of non-traditional sources like harvested rainwater and greywater. In addition, use of stormwater or reuse of wastewater raises public health concerns due to unknown risks and pathogen levels, thus rapid monitoring technologies and transparent reporting systems can facilitate their adoption. Finally, cost structure of desalination varies significantly around the world, largely due to regulatory requirements and local policies. Further reduction of its capital cost and energy consumption is identified as a hurdle for implementation. Overall, models and process analyses highlight the strength of comparative assessments across scenarios and water supply options.

气候变化、人口增长和未来水文不确定性的影响需要加强节水、开发新水资源以及转向可持续的城市供水组合。利用非传统水源实现水资源组合多元化可以发挥关键作用。屋顶收集雨水（RHRW）、大气和凝结水收集、雨水、回收废水和灰水、淡化海水和苦咸水都是目前正在利用和迅速崛起的非传统水源。本综述探讨了这些非传统水源的现状和趋势，并回顾了优先考虑、预测和量化关注指标的方法和模型。这里提出的分析表明，了解特定地点场景的挑战，社会经济知识差距、供水技术和/或水管理结构是建立模型或框架方法以提供未来改进战略的关键的第一步。这项研究的结果还表明，对于收集的雨水和灰水等非传统来源的可变水质问题，明确的政策指导和现场维护是必要的。此外，由于未知的风险和病原体水平，雨水的使用或废水的再利用会引起公众健康问题，因此快速监测技术和透明的报告系统可以促进其采用。最后，海水淡化的成本结构在世界各地差异很大，这主要是由于监管要求和当地政策的影响。进一步降低资本成本和能源消耗被认为是实施的障碍。总体而言，模型和过程分析凸显了跨情景和供水方案的比较评估的优势。