Two people were caught red-handed in Muldersdrift allegedly trying to fill tankers of water to drive down to the Western Cape on Wednesday night, the Mogale City Local Municipality said.
"This is a gross violation of the rights of the citizens of Mogale City," said Mayor Naga Lipudi in a statement.
Level 6B water restrictions kicked in in the City of Cape Town on Thursday, further limiting water consumption to 50 litres per person per day, in the hopes of avoiding "Day Zero".
The city and provincial government are putting in place plans to distribute a water ration of 25 litres per person per day, should Day Zero become a reality. Philanthropists are also arranging for bottled water to be trucked down.
Lipudi said the municipality sympathises with the City of Cape Town as it stares down the crisis, and would help with an official operation, but it would not allow water to be taken illegally.
"Theft is not the best solution! Taking this scarce resource from the people of Mogale City without asking is theft.
"Our people pay for water and everybody who uses it must pay. Unaccounted for water is one of the Auditor-General's matters of emphasis and therefore we must ensure that we account for each drop."
The bust was all down to the amateur detecting skills of local ANC ward councillor Molefi Sedibo who told News24 that he just knew "something was not right" when he spotted the double tanker as he drove past the water point in the Muldersdrift CBD.
Muldersdrift is situated about 30km north-west of Johannesburg.
Sedibo said the water point was there to serve the poor in the area who do not have access to running water. He said that having been a councillor for 10 years, he was familiar with the timetable followed by the trucks that usually fill their tanks at the water point and knew which service providers delivered the water.
"It was around 17:00 and normally those trucks have already finished work," he explained.
He had noted in the past that the drivers usually take the tankers back to the depot empty at the end of the day to save on diesel.
"Water is very heavy, so it is very expensive to drive the water to the depot, so they go back empty," he said.
His suspicions aroused, he also noticed that the tanker did not have the usual logo. He then blocked the tanker with his car, and got out to ask questions. Two of the four people working near the tanker bolted when they saw him.
He noticed that they had even brought the specialised equipment needed to connect to the system to get the water into the tanker.
"They got a fright when I started asking: 'Who gave you permission? Who are you?'" Sedibo recounted.
"I said: 'The truck will not move until you verify this'."
The driver and an assistant remained while safety officials arrived at Sedibo's beckoning. The two were taken to a police station for questioning.
A police spokesperson was not immediately available to establish whether they were charged.
Mayor Lipudi said the driver told the officers that the water was destined for the Western Cape, but he could not give clear answers on who the instruction to get the water came from.
In the meantime, Lipudi wants the police to take swift action because he has since heard from witnesses that it was the third time the truck had taken water without permission.
"Therefore, we want the authorities to get to the bottom of this as a matter of urgency so that we should know who runs a parallel government and doles out free water that belongs to the people of the city so boldly to anyone they feel like."