The union was founded on 24 October 1987, when the
Municipal Workers' Union of South Africa merged with the
Cape Town Municipal Workers' Association (CTMWA), and the municipal workers' sections of
General Workers' Union of South Africa,
South African Allied Workers' Union and
Transport and General Workers' Union. All of these unions were affiliates of the
Congress of South African Trade Unions, to which SAMWU also affiliated. In later years, SAMWU absorbed the
Durban Indian Municipal Employees' Society and the Union of Johannesburg Municipal Workers. Initially, the union grew rapidly, and by 1994 it had 100,410 members, 31.3% of all eligible workers. The union led opposition to privatisation schemes, and was particularly active in opposing the privatisation of a water treatment plant in
Johannesburg. In 2002, it led a national three-week strike for higher wages. In 2009, the union's leadership was voted out, and disagreements around this led the
Democratic Municipal and Allied Workers' Union of South Africa and the Municipal and Allied Trade Union of South Africa to split away over the next few years. In 2020, the union declared that it might withdraw support for the
African National Congress government. Membership of the union is open to South African workers employed, directly or indirectly, in local authorities, water utilities and allied undertakings of the economy whether in the public, private or voluntary sector, including: public administrative services in municipalities and local authorities, health and social services, libraries, cultural and other community services, water and sanitation, solid-waste management and environmental services, road construction and storm-water drainage, electricity generation and distribution, public transportation and traffic control, telecommunication and information services, scientific and technical services, and parks and recreation. ==Leadership==