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Gauteng urgently needs to reduce water consumption by 10% or face Day Zero

2 Sep 2024

Gauteng water consumption is simply unsustainable under present patterns of use. Putting it bluntly, the province faces Day Zero, and that is an undeniable fact.

In June this year the Platform for a Water Secure Gauteng (PWSG) was launched. I covered the event as an invited participant and wrote about it in Daily Maverick (“Platform for a water-secure Gauteng is a rebirth of hope, the best shot we will ever have”).

At the heart of that event was the stated intention of building consensus around the need to avoid Gauteng’s own Day Zero. Dr Sean Phillips, the director-general of the Department of Water and Sanitation (DWS), spoke in unambiguous terms, delivering one clear message: Gauteng needs to limit its water consumption by at least 10%, or 400 megalitres per day (that’s 400 million litres) if it is to avert Day Zero. This must be done in the next 12 to 24 months.

It is refreshing to hear a technically competent senior official speak with such clarity. The words are not alarmist, but they are factual. They intend to avert a disaster before it happens, but above all else, the words spoken with such confidence also set a very clear target that is attainable. But only if everyone cooperates.

So let us do a quick reality check on how society has responded. Facts are our best friends, so let’s take a sober look at some cold numbers devoid of emotion.

The first hard fact is that Rand Water is the single bulk water provider for the entire Gauteng region. The second is that Gauteng is the largest single contributor to the national economy. Third, Gauteng is home to three metros – Johannesburg, Ekurhuleni and Tshwane – which collectively distribute the bulk of the water supplied by Rand Water.

The many small municipalities in Gauteng, that are also sustained by Rand Water, are relatively insignificant compared with those three big bulk users.

The fourth hard fact is that water is an economic enabler, so there is a correlation between water supply and future economic prosperity.

Now let us look at the numbers. The first chart below shows the combined weekly consumption from the three Metros in Gauteng supplied by Rand Water from October 2022 to August 2024.

The red line represents the agreed level of consumption tied down into legal water-use licences approved by the DWS. This is an important number because it represents the maximum that can be supplied without the system collapsing, because stated simply, the DWS is responsible for balancing demand from multiple users with sustainable supply, in this case from the Integrated Vaal River System. For this reason, the red line is flat and fixed on the graphs.

The blue line is the actual consumption of each metro, and it varies over time due to a variety of factors, so it’s a squiggly pattern of consumption that shows major trends.

Gauteng water (Image: Supplied)

When the squiggly blue line falls below the straight red line, it means that water consumption is sustainable, because it is within the water use licence parameters determined by the DWS.

The converse holds true when the blue line moves above the red line; it simply means that demand exceeds the level of sustainable supply. Think of an overdraft facility on a bank account. The owner of that account can withdraw more cash from the bank than they have in their account, but it must be paid back if the bank is to remain in business.

If all account holders withdraw more than they have deposited in the bank, and never pay back, then the viability of that bank is in question. Unless it is bailed out by the Reserve Bank, it will fail.

This is exactly what happens with water, and this is the story being told by the data on the graph. But there is a third line. It is coloured green and it is lost in the overall noise of the data, but it’s of vital importance. That green line represents a target for responsible water use determined by benchmarking against known best practices. In short, the green line guarantees sustainability of supply over time.

Now let us analyse the data in more detail. From October 2022 until September 2023, all water users were operating within their licence obligations. Then, in July 2023, there was an event that manifests as a sharp but temporary decline in consumption, followed by a rapid growth in demand to a level above the red line. This manifests as a clear blip on the screen. The combined demand has remained consistently above the red line since October 2023.

What accounts for the blip on the screen in July 2023? The answer is found in the graph for the Johannesburg Metro.

(Image: Supplied)

During July 2023 there was a planned maintenance event, and the Metro called on all users to store water before the actual shutdown on Tuesday, 11 July. That communication triggered hoarding by consumers, which exacerbated the impact of the planned shutdown.

The lesson to be learnt from this is the need to keep the public informed and empowered with good advice before the planned maintenance.

If we look at the data from the City of Ekurhuleni, we see a similar event taking place in July 2024. As with Johannesburg, the reason was the same – planned maintenance on critical infrastructure that affected a defined area of the network.

(Image: Supplied)

However, the Ekurhuleni consumption patterns are similar to Johannesburg, also crossing over the red line in October 2023 and remaining consistently above the licence agreement value shown as the red line.

The City of Tshwane has an interesting water use pattern that differs fundamentally from the other two metros.

(Image: Supplied)

With the exception of a short period between November and December 2022, water consumption has been consistently in excess of the water-use licence value shown as the red line.

The interesting aspect of Tshwane’s water supply is that about 7.5% of its water use comes from groundwater. It happens to straddle the dolomites, a geological structure shared with Ekurhuleni, but generally not exploited by the latter for reasons beyond the scope of this article. Theoretically, this means that Tshwane can develop that alternative resource, provided that it manages the mining rights applications that will certainly impact negatively on the dolomite resource.

So, what does this all mean? In a nutshell, Gauteng water consumption is simply unsustainable under present patterns of use. Rand Water is simply unable to supply water in excess of the water-use licence granted by the DWS, and they, in turn, are unable to increase the legal abstraction levels if all water users are to be supplied in a fair and equitable manner.

This might change once Phase 2 of the Lesotho Highlands scheme comes online, but that is years into the future. Stated simply, unless the three metros urgently implement the water conservation strategies they have already agreed with the regulator, the system will crash.

Putting it bluntly, Gauteng faces Day Zero, and that is an undeniable fact.

But now for the good news. This is entirely avoidable if all metros do what they have agreed to do. This is the purpose of the PWSG – to inform the public in an honest and transparent manner about the risk status with the intention of reducing consumption and thereby avoiding Day Zero.

Rand Water is augmenting its infrastructure. This includes the planned addition of 1,200 million litres per day through Station 5 and the construction of a massive 210-megalitre (210 million-litre) concrete reservoir at Vlakfontein.

Significantly, if a simple reduction of 10% is achieved, then the crisis is averted. This is a smaller target than the Cape Town case in 2018, so it is doable. Let us simply do it. DM

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