What Motivates People to Use Less Water?
During a drought, households can be inundated by messages to conserve water. We talked to Katrina Jessoe—an economist at UC Davis and a member of the PPIC Water Policy Center’s research network―about new research on what motivates people to conserve water.
PPIC: Talk about your recent research on water conservation messaging. What did you learn?
Katrina Jessoe: We partnered with a municipally owned water and electric utility to see how people would respond to additional water conservation messaging during summer 2015―at the height of the latest drought. These households were already receiving statewide and utility messages and incentives to conserve water. Our focus was to gauge if social comparisons would lead to additional conservation.
The utilities sent bi-monthly home water reports to a random sample of households. These reports compared a household’s water use to that of neighbors, gave recommendations on how to conserve water, and provided information on particular conservation programs being used by that utility.
We looked at how people responded and found that households that got these reports saved more water than those that didn’t. The reports prompted a reduction in water use of 3 to 4.5%, on top of water savings already prompted by other conservation programs. Interestingly, these water reports led to reduced electricity use as well—participating households used 1.3% to 2.3% less electricity that summer.
Similar home energy reports, which are being deployed throughout the US, are typically cited as leading to 1.3% to 2.5% reduction in energy use. These home water reports reduced electricity use by similar amounts as the energy reports while also reducing water use—even though electricity use wasn’t the target.
We were also able to see that people reduced their electricity use during peak hours—which is when electricity is most expensive and less likely to be produced from clean energy sources like renewables. This has ramifications for greenhouse gas emissions and the cost of providing energy. So this program was providing more bang for the buck than just water conservation.
Why should policy makers care? If you think about this from a cost effectiveness angle, saving water alone may not justify these kinds of interventions. But with the additional electricity savings, it increases the net benefit of these reports by almost two-thirds. We talk a lot about the water-energy nexus, but typically it’s about “embedded” energy savings—if you reduce water use by a gallon, what is the energy savings from treating and moving that water. This research documents the end-use savings in electricity from a water conservation instrument.
PPIC: What other tools show promise for encourage conservation?
KJ: We’ve looked at the City of Modesto, which moved from a flat fee type of billing to charging per unit of water. The utility took a unique approach to rolling out its pricing change. About every six months the utility switches a number of households to the new volumetric pricing system. Households receive a letter informing them when they will be switched to volumetric prices. For two billing periods they also receive a hypothetical bill informing them what their bills would be under the new system, though they continue to pay a flat rate for water.
We find that households reduce water use in response to both the actual price change and the earlier message with the hypothetical price change. The reduction in water use persists for more than two years after the switch to volumetric pricing. While still preliminary, these results highlight that when customers are informed about price changes, they respond to them. This suggests that price may be an effective tool to manage water use, if customers are well informed about the change.