The water tankers are not enough to keep residents supplied, he added.

An older resident, Thabisile Mchunu, said her taps have been dry since last week. She now hauls what water she can find in 20-liter buckets.

“The sad thing is that we don’t know when our taps are going to be wet again,” she said.

Rand Water, the government entity that supplies water to more than a dozen municipalities in Gauteng province, this week pleaded with residents to reduce their consumption. The interlinked reservoirs supplying its system are now at 30% capacity, and high demand on any of them affects them all.

Even South Africa’s notoriously troubled electricity system has played a role in the water problem, at least in part.

On Tuesday, Johannesburg Mayor Kabelo Gwamanda said a power station that supplies electricity to one of the city’s major water pumping stations had been struck by lighting, causing the station to fail.