GB/T 18920-2002 regulates the water quality of urban wastewater regeneration used as urban miscellaneous water. At a time when water resources are becoming increasingly tight, wastewater recycling is of great significance. This standard formulates water quality limits covering pH value, dissolved solids, five-day biochemical oxygen demand, ammonia nitrogen and other indicators according to different uses of urban miscellaneous use, such as road cleaning, toilet flushing, green irrigation, etc. At the same time, it specifies the requirements of microbial indicators to ensure the safety of use. It also stipulates the relevant methods and Frequency of water quality testing. Provide a basis for the compliance of urban sewage reclaimed water for miscellaneous use scenarios, and promote urban water conservation and sustainable utilization of water resources.