Psychology study helps lower water use in Encinitas


Cal State San Marcos researchers have tapped behavioral sciences to help the Olivenhain Municipal Water District achieve state-mandated water cuts.

University interns this summer handed out door hangers with five different conservation messages to 11,000 households in the district, and the researchers later tracked water use at these homes to see how residents responded.

A “collective action and commitment” door hanger netted the best results — a 6.5 percent drop in water use.

This hanger featured examples of residents reducing their water use, which worked because people tend to follow the behavior of the group, said Christine Jaeger, a CSUSM graduate student and project manager on the study. So it’s key to show instances reinforcing that conservation is a community norm.

The bottom of the door hanger asked residents to sign a pledge to conserve, and about a third did so. Interns then returned the next day to pick up signed commitments.

“We know that commitments are generally effective,” Jaeger said. “They solidify a behavior. And signing your name is a pretty strong commitment — stronger than checking a box, for instance.”

The 6.5 percent reduction is an average of July, August and September of this year. Monthly totals in the study were compared with use in June 2015, the first month in which water agencies across California were required to cut back in response to a punishing drought.

It’s common for water agencies to put up door hangers that simply list drought restrictions, but that traditional messaging doesn’t appear to be effective. The study found this information-only approach reduced use by 2.5 percent from July to September — about the same as a control group that didn’t receive any materials.

“When we give people just information, it’s not really motivating,” Jaeger said. “They need a little kernel of motivation to follow through.”

She added that past conservation research, known for looking at curbside recycling, has established the importance of pledges in sparking behavior changes. Studies have shown that in non-recycling households, recycling increased substantially for those who made a commitment.

Another batch of door hangers, which had a reminder of penalties for violating drought restrictions and then a request for a signed commitment, worked second best with a 4 percent drop. The message was most effective in the first month, but water savings quickly declined over the next two months.

The study also analyzed how those with especially green lawns responded to the five messages in July. Among them, the “penalties and commitment” door hanger was the least effective of all approaches, with a 4.5 percent drop.

“They probably didn’t appreciate this reminder they could be penalized — maybe they heard it before,” Jaeger said. Given the findings, water districts may want to go easy on language that threatens penalties when dealing with these customers, she said.

On the other hand, the “collective action and commitment” door hanger sparked a 15.7 percent drop for those with green lawns in July, as opposed to a 10.4 percent decline in the general population.

“These findings suggest that commitments made after receiving collective action information lead to long-term water reductions,” the study states.

The Olivenhain district is just exceeding its state-imposed mandate to slash water use 32 percent when compared with baseline months in 2013. The study is comparing July, August and September of 2015 water use with June of this year, and before the studied months, water consumption had fallen.

Joey Randall, customer services manager with the district, said the study is partly responsible for the continued decline in water use, helping the district surpass the state requirement.

Randall said the water district soon plans to retool its customer drought communications with the study in mind.

“We do know that only putting the drought restrictions on paper doesn’t seem to cut it,” Randall said. “Potentially because people have seen those so many times — they’re desensitized.”

Jaeger said it’s likely that a variety of messages are needed to persuade customers to cut back long-term, from reminders of penalties for violating drought restrictions to highlighting community efforts to conserve. But that’s as long as these opposing messages don’t appear on the same door hanger.

She added that residents’ pledges to save water are critical, but these requests also have to be varied over time.

“It probably wouldn’t be effective to ask the same households to make the same commitments over and over again,” she said.

Besides conservation messaging, the Olivenhain district has met its target by increasing water rates and stepping up enforcement. However, district officials have stated they’d prefer education when possible, a big reason they partnered with the university.

In May, the district’s board approved $48,191 to cover many of the study costs.

The Olivenhain district includes 20,000 households and covers the eastern half of Encinitas, parts of Carlsbad, Elfin Forest and 4S Ranch. Most of the households in the study were in Carlsbad and Encinitas.

Jaeger said the university is open to sharing the research with more water agencies.

“Our goal was to create something that’s scalable,” she said.