According to laws and regulations, how often should the tap water tanks in residential buildings be cleaned?

This is stipulated by the provinces, autonomous regions and municipalities directly under the central government according to local conditions. For example, Lanzhou City, Gansu Province, Kunming City, Yunnan Province, Guizhou Province and Chengdu City, Sichuan Province require annual cleaning; Xi City of Shaanxi Province, Guiyang City of Guizhou Province, Yongchuan City of Hainan Province, Shaoguan City of Guangdong Province, Shantou City, Zhongshan City and Jiangmen City require cleaning once every six months; Zhuhai City, Guangdong Province requires cleaning at least twice a year. It is recommended to consult the local health or relevant authorities.