The All-Japan Water Supply Workers' Union (Japanese: 全日本水道労働組合, Zensuido) is a trade union representing workers in the water industry in Japan.
The union was founded in 1951 by municipal workers involved in water supply and sewerage.
[1] The union affiliated to the General Council of Trade Unions of Japan, and by 1967, it had 31,699 members.
[2] It has been affiliated to the Japanese Trade Union Confederation since the late 1980s.
By 2020, its membership had fallen to 16,281.