Water temperature is often monitored at water sources and treatment works; however, there is limited monitoring of the water temperature in the drinking water distribution system (DWDS), despite a known impact on physical, chemical and microbial reactions which impact water quality. A key parameter influencing drinking water temperature is soil temperature, which is influenced by the urban heat island effects. This paper provides critique and comprehensive summary of the current knowledge, policies and challenges regarding drinking water temperature research and presents the findings from a survey of international stakeholders. Knowledge gaps as well as challenges and opportunities for monitoring and research are identified. The conclusion of the study is that temperature in the DWDS is an emerging concern in various countries regardless of the water source and treatment, climate conditions, or network characteristics such as topology, pipe material or diameter. More research is needed, especially to determine (i) the effect of higher temperatures, (ii) a legislative limit on temperature and (iii) measures to comply with this limit.

中文翻译：

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全球饮用水温度：理解、政策、挑战和机遇

通常在水源和处理厂监测水温；然而，尽管已知对影响水质的物理、化学和微生物反应有影响，但对饮用水分配系统 (DWDS) 中水温的监测有限。影响饮用水温度的一个关键参数是土壤温度，它受城市热岛效应的影响。本文对当前有关饮用水温度研究的知识、政策和挑战进行了批评和全面总结，并介绍了国际利益相关者调查的结果。确定了监测和研究方面的知识差距以及挑战和机遇。该研究的结论是，无论水源和处理方式、气候条件或网络特征（如拓扑、管道材料或直径）如何，DWDS 中的温度都是各国新出现的问题。需要更多的研究，特别是确定 (i) 较高温度的影响，(ii) 对温度的立法限制和 (iii) 遵守该限制的措施。