Technical problems have delayed the process of testing for possible water contamination in Diepsloot, the City of Johannesburg said on Saturday.
The city's networks team had expected to be done by 8pm on Friday but had encountered technical problems, spokeswoman Millicent Kabwe said in a statement.
"We have been on site the whole night and should be concluding the technical work in the next two to three hours. Once that is complete, we will take samples and it takes about 18 hours for the test to mature and get results," Kabwe said.
Residents had been issued a warning not to use tap water, as it may be contaminated.
The tests would determine which areas were affected and what caused the contamination. In the meantime residents were urged to continue using water from tankers.
Kabwe said more tankers were being deployed to cater for businesses in the area. -Sapa