Cape Town's water usage: did the drought create a long-lasting change in behaviour?

Cape Town residents queue for water as day-zero approaches © EPA

Following the drought that almost left Cape Town with no water, citizens cut back consumption dramatically. But have they managed to keep water usage down now that the rains have returned? A visual investigation by OpenUp, Adam Oxford and Jason Norwood-Young

News that President Elect Joe Biden plans to commit the USA to the climate change targets of the Paris Agreement cannot be greeted with anything other than a sigh of relief. Even allowing for the drop in carbon emissions due to the pandemic and new targets from European governments, it’s not been a great couple of years for Planet Earth. Trump’s refusal to commit the world’s largest polluter to change, combined with record deforestation in the Amazon (thanks Bolsanaro) and rising coal use in China and India especially has led to a bleak outlook for the future. 

Much of South Africa is highly vulnerable to the effects of the climate crisis.

We can’t stop the climate crisis. Even if, somehow, Joe Biden, Xi Jingping, Narendra Modhi and Jair Bolsanaro -- in fact all the world’s leaders -- could somehow come up with a plan to hit the Paris target, we will still be in uncharted territory as far average temperatures go. The name of the game now is climate resilience -- how do we learn to live with the impact of a couple of centuries of industrialisation?

Much of South Africa is highly vulnerable to the effects of the climate crisis. The farmlands of the Free State to the Karoo, the Eastern Cape and, of course, the Western Cape are already feeling the effects. So are we changing our habits?

One place we thought we’d look for evidence is in water usage in Cape Town. After hitting Day Zero, when the taps ran dry three years ago, Capetonians made a staggering effort to reduce the amount of water they used on a daily basis. With that particular crisis behind them (which was a result of many natural and man-made causes operating together, but made five times more likely thanks to climate change) have they reverted back to old norms or have they adopted a more cautious attitude?

Why Cape Town?

The obvious reason is that the scale of behavioural change required over a long period of time to manage water resources was almost unprecedented in a reasonably affluent global city (yeah, we know about Sao Paulo etc). The second reason is that Cape Town has a reasonably good open data portal that includes lots of information about water usage at the suburb level, going back to 2015 (https://web1.capetown.gov.za/web1/opendataportal/AllDatasets). And the local government has committed to maintaining that portal so that citizens and researchers can do exactly this kind of exercise.

Except that what we found, when we started looking at the difference between suburban usage before, during and after the crisis left us feeling a bit depressed. This was a far harder exercise than it should have been, and the resulting analysis cannot be published without a host of caveats. 

It’s depressing because at least Cape Town is publishing this data, even if it is not in formats that are terribly usable without a lot of cleaning.

For a start, the way data is captured and published changes at least four times in a six year period. The 2017-2018 period records average water use per property, leaving us to interpolate suburb level data based on housing statistics. From 2019 on, it is recorded in a completely different way that focuses more on the financial aspect of water management (ie. billing) than actual usage. Many suburbs in 2019-2020 show massive over-usage and then corrections month after month and there’s a lack of consistency in the units of measurement. A single column recording use per suburb switches between litres and kilolitres, for example. 

By the time we get to 2020, however, things get even worse. A change of publishing format appears to have stripped usage data from a large number of areas, and what is recorded seems inconsistent with previous years. For these reasons, we have decided not to include this year’s records in our infographic. We have also excluded suburbs which show large inconsistencies over time that cannot be easily explained by the crisis.

It’s depressing because at least Cape Town is publishing this data, even if it is not in formats that are terribly usable without a lot of cleaning. That’s more than most other local governments, so we have to give credit for implementing an open data policy. Given the magnitude of the water crisis in Cape Town itself, and the importance of planning on a national scale to improve climate resilience, we have to advocate for better access to this kind of data for all.

What have we found?

Given our lack of confidence about the data, we selected 50 suburbs which we are fairly confident that the water usage recorded is comparable over a period of four years from 2016 to 2019. We have not adjusted the figures for changes in population or seasonal variation, so there will be some errors. If you’re aware of any, we’d love to know. We should also point out that we only looked at data relating to domestic usage, not commercial. 

Overall, there’s a 26% decline in water usage across the suburbs we tracked, but for those that are saving water the reduction is a third.

The good news is that the water-saving efforts in Cape Town appear to be ongoing. With the exception of five suburbs we looked at (Kenilworth, Muizenberg, Observatory, Sea Point and Sunnydale) water usage is well below the levels seen in 2016, before the crisis hit hard. 

In the few suburbs that have seen water usage go up, the average rise is 26% -- and almost 50% in Sea Point.

Overall, there’s a 26% decline in water usage across the suburbs we tracked, but for those that are saving water the reduction is a third. In the few suburbs that have seen water usage go up, the average rise is 26% -- and almost 50% in Sea Point.

Our conclusion? This issue is not going away and we need better data to help build resilience. We may be having a wet summer and dam levels across the country are looking better than they have for a while, but if we’re going to avoid the next Day Zero, we can’t become complacent even now.

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Following the drought that almost left Cape Town with no water, citizens cut back consumption dramatically. But have they managed to keep water usage down now that the rains have returned? A visual investigation by OpenUp, Adam Oxford and Jason Norwood-Young

News that President Elect Joe Biden plans to commit the USA to the climate change targets of the Paris Agreement cannot be greeted with anything other than a sigh of relief. Even allowing for the drop in carbon emissions due to the pandemic and new targets from European governments, it’s not been a great couple of years for Planet Earth. Trump’s refusal to commit the world’s largest polluter to change, combined with record deforestation in the Amazon (thanks Bolsanaro) and rising coal use in China and India especially has led to a bleak outlook for the future. 

Much of South Africa is highly vulnerable to the effects of the climate crisis.

We can’t stop the climate crisis. Even if, somehow, Joe Biden, Xi Jingping, Narendra Modhi and Jair Bolsanaro -- in fact all the world’s leaders -- could somehow come up with a plan to hit the Paris target, we will still be in uncharted territory as far average temperatures go. The name of the game now is climate resilience -- how do we learn to live with the impact of a couple of centuries of industrialisation?

Much of South Africa is highly vulnerable to the effects of the climate crisis. The farmlands of the Free State to the Karoo, the Eastern Cape and, of course, the Western Cape are already feeling the effects. So are we changing our habits?

One place we thought we’d look for evidence is in water usage in Cape Town. After hitting Day Zero, when the taps ran dry three years ago, Capetonians made a staggering effort to reduce the amount of water they used on a daily basis. With that particular crisis behind them (which was a result of many natural and man-made causes operating together, but made five times more likely thanks to climate change) have they reverted back to old norms or have they adopted a more cautious attitude?

Why Cape Town?

The obvious reason is that the scale of behavioural change required over a long period of time to manage water resources was almost unprecedented in a reasonably affluent global city (yeah, we know about Sao Paulo etc). The second reason is that Cape Town has a reasonably good open data portal that includes lots of information about water usage at the suburb level, going back to 2015 (https://web1.capetown.gov.za/web1/opendataportal/AllDatasets). And the local government has committed to maintaining that portal so that citizens and researchers can do exactly this kind of exercise.

Except that what we found, when we started looking at the difference between suburban usage before, during and after the crisis left us feeling a bit depressed. This was a far harder exercise than it should have been, and the resulting analysis cannot be published without a host of caveats. 

It’s depressing because at least Cape Town is publishing this data, even if it is not in formats that are terribly usable without a lot of cleaning.

For a start, the way data is captured and published changes at least four times in a six year period. The 2017-2018 period records average water use per property, leaving us to interpolate suburb level data based on housing statistics. From 2019 on, it is recorded in a completely different way that focuses more on the financial aspect of water management (ie. billing) than actual usage. Many suburbs in 2019-2020 show massive over-usage and then corrections month after month and there’s a lack of consistency in the units of measurement. A single column recording use per suburb switches between litres and kilolitres, for example. 

By the time we get to 2020, however, things get even worse. A change of publishing format appears to have stripped usage data from a large number of areas, and what is recorded seems inconsistent with previous years. For these reasons, we have decided not to include this year’s records in our infographic. We have also excluded suburbs which show large inconsistencies over time that cannot be easily explained by the crisis.

It’s depressing because at least Cape Town is publishing this data, even if it is not in formats that are terribly usable without a lot of cleaning. That’s more than most other local governments, so we have to give credit for implementing an open data policy. Given the magnitude of the water crisis in Cape Town itself, and the importance of planning on a national scale to improve climate resilience, we have to advocate for better access to this kind of data for all.

What have we found?

Given our lack of confidence about the data, we selected 50 suburbs which we are fairly confident that the water usage recorded is comparable over a period of four years from 2016 to 2019. We have not adjusted the figures for changes in population or seasonal variation, so there will be some errors. If you’re aware of any, we’d love to know. We should also point out that we only looked at data relating to domestic usage, not commercial. 

Overall, there’s a 26% decline in water usage across the suburbs we tracked, but for those that are saving water the reduction is a third.

The good news is that the water-saving efforts in Cape Town appear to be ongoing. With the exception of five suburbs we looked at (Kenilworth, Muizenberg, Observatory, Sea Point and Sunnydale) water usage is well below the levels seen in 2016, before the crisis hit hard. 

In the few suburbs that have seen water usage go up, the average rise is 26% -- and almost 50% in Sea Point.

Overall, there’s a 26% decline in water usage across the suburbs we tracked, but for those that are saving water the reduction is a third. In the few suburbs that have seen water usage go up, the average rise is 26% -- and almost 50% in Sea Point.

Our conclusion? This issue is not going away and we need better data to help build resilience. We may be having a wet summer and dam levels across the country are looking better than they have for a while, but if we’re going to avoid the next Day Zero, we can’t become complacent even now.

Embed this visualisation

<div class="flourish-embed flourish-chart" data-src="visualisation/4651425"><script src="https://public.flourish.studio/resources/embed.js"></script></div>

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