Using behavioural interventions to encourage water conservation.



San Antonio Water System


Reducing water consumption in a context of water scarcity

Maintaining lawns and gardens is a significant drain on Texas’ scarce water resources. Encouraging households to reduce water consumption and replace lawns with water efficient plants can provide savings for households as well as reduce the risk of drought. We partnered with San Antonio Water System (SAWS), a water utility with an active history of promoting conservation measures, to inform policymakers on the most effective interventions for promoting technology adoption as a means of managing residential water use.


Encouraging the adoption of water conservation technologies

We designed letters incorporating social norm messaging, pro-social rewards, and financial incentives and tested these in a randomised controlled trial.

The aim of the experiment was to explore methods to reduce the water use of these customers through changing the “landscape stock,” i.e., encouraging households to switch to less water-intensive landscaping arrangements. In particular, SAWS wished to encourage “WaterSaver” landscaping that utilises drought-resistant plants and shrubs, which can survive with little or no irrigation.

We tested four treatments designed to encourage the adoption of a turf-replacement technology and water conservation, sending letters to approximately 23,000 residential homes, reminding them of the existence of a rebate for partially replacing their lawn with drought-resistant plants. Through our partnership, we are able to measure behaviour across a variety of margins that influence overall patterns of water use. Our intervention increased the uptake of lawn replacement by 36% & reduced water consumption by 1.4%.

Results from the experiment suggest several interesting findings regarding both the adoption decision and subsequent patterns of water use. Financial incentives generated an increase of 36% in the uptake of drought resistant plants. The social norm messaging reduced water consumption by 1.4% but did not increase the uptake of lawn replacement.

This experiment demonstrated the relative benefits of different types of messaging and highlighted how small changes in the framing of information can induce large shifts in efficient technology adoption behaviour.

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