California water agencies face increasing pressure to promote and implement sustainable water conservation practices. But as the old saying goes, “old habits die hard.” So what motivates people to use less water?

New information from the Public Policy Institute of California (PPIC) may provide important insight into this question.

Dr. Katrina Jessoe, a professor and economist at UC Davis and a member of the PPIC Water Policy Center’s research network, is one of the researchers studying water conservation messaging to determine what strategies are most effective in motivating consumers to use less water. Her research team partnered with a municipally-owned water and electric utility to see how people would respond to additional water conservation messaging during the height of the last drought in the summer of 2015.

Although the households were already receiving statewide and utility messages and incentives to conserve water, Jessoe’s research team wanted to gauge whether social comparison tactics would produce additional conservation. The utility 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,” said Jessoe. “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.”

Additional water conservation, however, was not the only benefit. Jessoe’s team found that the water reports also led to reduced electricity that summer—1.3% to 2.3% less. This was a particularly interesting find as home energy reports are shown to lead to similar energy reduction results as the home water reports, despite the fact that electricity was not the target. In other words, the home water report offered “more bang for your buck” in terms of resource conservation.

“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,” Jessoe explained. “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.”

Perhaps unsurprisingly, Jessoe’s other research has indicated that pricing and price change messaging are additional strategies that are effective in reducing household water use. Jessoe cited 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,” explained Jessoe. “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.”

Jessoe’s team found that households reduce water use in response to both the actual price change and the sample bill with the hypothetical price change. Moreover, they found that the decrease in water use continues for more than two years after the switch to volumetric pricing.

These findings suggest that price may also be a motiving factor to reduce water use, when accompanied by timely, effective messaging.

For more information, see the original article published by Lori Pottinger on the PPIC blog.