Carrot-or-stick to ‘nudge’ water-wise behaviour

There are many ways for city utility departments to get people to voluntarily reduce their water use during a time of drought and water shortages. Some are positive, ‘carrot’ approaches; others might be ‘stick’ approaches to enforce certain behaviours. Now, the City of Cape Town is working with behavioural economists to find an evidence-based answer to which methods are most effective.

The results will assist the municipality design policy that will help manage the city’s water supplies in an increasing climate changed-stressed future. However researchers argue that the results of this study are more widely applicable to behaviour in other areas, such as cutting energy use, or waste reduction and recycling.

The City of Cape Town has been working with researchers from the Environmental Policy Research Unit (EPRU) at the University of Cape Town for two years, to test the effectiveness of various carrot-and-stick approaches to encouraging more prudent water use by the public.

Traditional ‘stick’ approaches usually include water price hikes and tiered tariff structures, or water restrictions.

Other ‘stick’ approaches used more recently, included naming-and-shaming. In February this year, the city published the addresses of the 100 biggest domestic water users in the metropole. It also sent private letters, in people’s utility bills, to households whose water use is greater than 50 kilolitres (kl) a month. The letters highlighted the high water use, and indicated that water restriction devices would be implemented if households didn’t change their behaviour.

A ‘carrot’ approach includes methods tested recently by researchers and the city to use ‘behavioural nudges’ to drive greater water-wise behaviour. This means using simple interventions that are geared towards encouraging people to make better decisions in a context such as this, where a city needs to alleviate its water crisis. These behavioural nudges used various positively framed messages, also sent out in people’s utility bills, to encourage voluntary water reduction behaviours.

  • Read more about the behavioural nudges experiment here.

Researchers have observed the water use patterns in various communities across the city during this time, as these different approaches have been implemented. Their intention now is to analyse the data they have gathered, and compare how effective these different methods are.

Thereafter, researchers and the city will begin to consider how these evidence-based findings can be integrated into municipal processes and policies, to shape future water management.

These findings are particularly relevant now, following three years of drought across the region. By the summer of 2017, only about 20 percent of the water left in Cape Town’s dams was accessible, resulting in extensive water restrictions. A changing climate will make these sorts of droughts and associated water management challenges more commonplace in future.

EPRU researchers now hope to work with other municipalities around the country, to see if they can engage in similar mutual learning process. This will be through national workshops where big municipalities will be invited to see how they, too, can incorporated these evidence-based ideas into their policies.

The research was funded jointly by the South African National Research Foundation, the Norwegian Research Council, and the Water Research Commission. The EPRU team was supported by Samantha De Martino from Sussex University, and Jorge Garcia from Cicero in Norway.


Story | 18 April 2017