Heatwave and water demand: Could hot weather strain SA’s water supply?

South Africa’s prolonged heatwave is driving up water demand and putting additional pressure on already strained water supply systems.

A strong El Niño could prolong warmer-than-normal conditions into 2027, raising further concerns about water availability.

The Department of Water and Sanitation (DWS) has urged residents, especially in Gauteng, to save water as demand rises ahead of the 2026/27 summer season.

Department spokesperson Wisane Mavasa said the current heatwave, which has entered its third consecutive week, is increasing water demand across Gauteng.

“This is compounding existing challenges, particularly substantial water losses through leaking municipal distribution infrastructure and high average consumption per capita in certain areas,” Mavasa said.

The department warned that excessive water use in areas with reliable supplies could worsen shortages in communities already experiencing water supply disruptions.

Gauteng residents use more water

DWS figures show that Gauteng residents consume approximately 250 litres of water per person daily, well above the international average of 173 litres.

The province also loses significant volumes of water through its supply system.

Non-revenue water stands at an estimated 47%, with physical water losses accounting for about 27%.

These figures highlight the pressure on water resources as households increase consumption during prolonged hot conditions.

El Niño raises concerns about prolonged heat

The heatwave comes as the World Meteorological Organization (WMO) warns that a very strong El Niño could intensify global heat and extreme weather risks well into 2027.

The anticipated El Niño could also influence rainfall patterns, increasing the risk of below-normal rainfall in parts of southern Africa.

For South Africa, reduced rainfall could limit dam inflows, while higher temperatures could increase evaporation and household water consumption.

DWS cannot provide additional water to Rand Water

DWS has stressed that it cannot simply increase water allocations to meet rising demand.

The department allocates Rand Water an annual abstraction volume from the Integrated Vaal River System (IVRS).

It only adjusts allocations when severe drought conditions or long-term assessments justify a change.

Mavasa said the department could not provide Rand Water with additional water beyond its authorised allocation.

She urged residents to reduce consumption by taking shorter showers, repairing leaking taps and pipes.

Turning off taps when brushing their teeth and limiting garden watering to between 6pm and 6am.

Residents must also follow municipal water-use restrictions. This includes limits on hosepipes, vehicle washing and swimming pool maintenance.