Johannesburg Water (JW) confirmed the status of critically low systems on Friday, include the Grand Central Tower, the President Park Reservoir, in Midrand.
JW has had to close the Alexander Park Reservoir temporarily, in order to build capacity.
But some systems are struggling due to a power outage.
This is the case with the Waterval Tower, which is critically low, due to an outage affecting parts of Randburg.
Similarly, no electricity supply has led to low levels in towers in Heldekruin, Florida North, Constantia and Horizon.
An outage South of Joburg, is affecting reservoirs in Orange Farm, Lawley and Ennerdale.
An isolated case of a burst pipe, has led to interrupted supply in Jabulani, Soweto.
Affected areas are Jabulani, Moletsane, Tladi, Molapo, Moroka, Mapetla, Phiri and Dlamini.
All other systems in the City are supplying fairly and deemed stable.