Rand Water said although planned maintenance of water systems supplying Gauteng was completed on Saturday, pumping has not yet returned to full capacity.
Some reservoirs remain critically low, which means users may continue to experience low water pressure or no water in certain areas.
Alternative water supply is being provided through stationary and roaming water tankers.
Johannesburg Water said systems under pressure include the Commando, Crosby, Brixton, Hursthill 1 and 2.
Similarly, the Central system, which supplies many Southern suburbs, is also under pressure.
Some residential areas have little to no water at several areas including those supplied by the Eagle Nest reservoir, Northcliff, Crown Gardens, Aeroton, Alexander Park, South Hills, Parktown, Berea, Yeoville, Forest Hill and Hector Norris.
Affected areas in Roodepoort include the Heldekruin reservoir, Witpoortjie, Constantia, Florida North and Horizon Tower.
The City of Ekurhuleni confirmed the Zulu and Xhosa reservoirs were critically low. The Zulu reservoir supplies Tsakane Extension 1, 5, 8, 11 and Geluksdal, while the Xhosa one extends to parts of Tsakane Proper and Tsakane extensions 9, 10, 12b, 15, 16 and 17.
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