JOHANNESBURG - Joburg Water is warning that levels of reservoirs linked to the Zuikerbosch plant are critically low to empty.
The purification plant is not operational due to a power outage.
It's affecting the President Park, Rabie Ridge, Honeydew and Linksfield reservoirs.
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The utility is warning of reduced supply in Midrand, the eastern and southern parts of the city and the Commando system of Brixton, Crosby and Hursthill.
Water tankers are being deployed to affected areas.
Meanwhile, repairs to a major burst in Houghton have been completed.
The reservoir outlet has been reopened, but the utility warns it will take some time to fully restore supply.