Joburg Water‚ the Rand Water Board‚ Naturena‚ Alveda‚ South Fork and Loughrin were still without power early on Tuesday after a fire at the Eikenhof substation‚ south of Johannesburg.
City Power said on Tuesday that it had only managed to restore power to the Kibler Park area.
"City Power engineers and technicians are still on site‚ ready to work throughout the night to repair and replace damaged infrastructure‚" said CEO Lerato Setshedi.
"We have all our teams here on the ground to ensure this is resolved as soon as it's humanly possible‚" she added.
The transformer caught alight on Monday afternoon‚ plunging many parts of Johannesburg into darkness.
Rand Water issued a statement‚ saying the fire would disrupt the supply of water to the western parts of the city‚ as well as to Rustenburg in the North West.