“Drinking the same river water.” “Water” is the “bond” of the Guangdong-Hong Kong-Macao Greater Bay Area and closely connects the “9+2” cities. The systematic management of the water environment of the Guangdong-Hong Kong-Macao Greater Bay Area has great practical significance and far-reaching historical significance. Relevant research shows that with the rapid development of cities in Guangdong，problems such as the lack of drainage networks，high population density，and scattered industries and their layouts are prominent. Water pollution treatment lacks systematicity and scientificity，river pollution interception methods are single，and governance measures are eager. Seeking success，failed to form a systematic management idea and management system；even if a large amount of manpower and material resources were invested，reducing sewage discharge was still slow，and the effect of improving water quality was not great. Proceeding from the reality of the water environment，it is necessary to conduct benchmarking internationally，system design，classified policy，and coordinated advancement to realize the integration of water supply，drainage，water treatment，reclaimed water utilization，and sponge city construction，and to form a replicable and scalable water environment governance model. Only a good ecological environment，especially a clean water environment，can support the sustainable economic and social development of the Guangdong-Hong Kong-Macao Greater Bay Area and build the Guangdong-Hong Kong-Macao Greater Bay Area into a world-class city cluster and innovation center.