JOHANNESBURG - Rand Water has begun its major maintenance programme.
The first day may see taps in Ekurhuleni, Tshwane and parts of Mpumalanga run dry.
The project is expected to run until Monday.
The utility says it's essential to boost system capacity and to ensure long-term stability.
The work is being carried out in phases, with parts of Mpumalanga, North West and the Free State affected.
Water tankers will be deployed to affected communities during the outages.