Abstract: Objective To fully understand the history, current situation and major health-related problems of dual piping water supply, and to investigate the sanitary situation of the dual piping water supply system in Shanghai.Methods 10 suppliers and 35 employees, as well as 175 apartment owners were investigated by data collecting, field survey, and individual interview.Results The development of dual piping water supply industry in Shanghai slowed down gradually since 2008, and nearly stagnated at present. Only 30%-50% of households choose dual piping water supply on average. Talents shortage and payment in arrears were the major obstructions to the development of the industry. Most users considered dual piping water supply as one of the reasons of apartment purchase, while some apartment owners did not use it because they used water purifiers as substitute or they believed that tap water quality was good enough. Qualification rate of both health inspection and water quality were above 95%. Due to design deficiency and low utilization of water supply network, the quality of back water and tap water of dual piping water supply was worse than the quality of water directly taken from the water processing equipment, both differences were significant(P<0.05).Conclusion There is still certain demands in the market of dual piping water supply. However, there are hidden sanitary dangers in the industry due to its stagnant development and low enthusiasm of operators and lack of governance. Therefore, it is suggested that governance should be clarified, new operational method should be explored and inspection mechanism including social engagement should be built to ensure the sanitation and safety of dual piping water supply.