Free Smart Irrigation Controllers Reduced Outdoor Water Use by 17% in Spanish Fork, Utah

By reducing complexity, the city of Spanish Fork nudged homeowners to make significant irrigation reductions, which helped to save on costly infrastructure upgrades.

In 2018, Spanish Fork was managing growing peak demand on its pressurized irrigation system. The city operates a separate non-potable irrigation network, installed in 2002, that supplies water for outdoor irrigation and reduces demand on the drinking-water system. City officials expected peak demand to eventually exceed existing system capacity, creating pressure to expand water rights, storage, or other infrastructure.

The city’s solution: Offer eligible residents a free Rachio smart irrigation controller, professional installation, and a recommended irrigation schedule designed to reduce unnecessary watering and stagger demand during peak-use periods.

Spanish Fork’s irrigation system experiences strong peak demand in the early morning and late evening, when many customers schedule automatic sprinklers. The city’s recommended smart-controller schedules were designed to spread irrigation across different time periods and account for local weather conditions. Spanish Fork’s conservation plans also advise customers to avoid watering during high winds and the heat of the day.

Spanish Fork was facing another challenge. Utah’s municipal and industrial water-conservation plan set a statewide goal of reducing average per-capita water use from 295 GPCD in 2000 to 220 GPCD or less by 2025. Spanish Fork’s program was part of the city’s broader effort to reduce demand and manage future growth.

How the Program Worked on the Ground

The pilot project harnessed several concepts of “choice architecture,” as described in the bestselling 2008 book Nudge: The Final Edition (revised 2021). People tend to follow the default path, and they become more motivated by seeing the relevance of their actions. The 2010 UK government publication MINDSPACE: Influencing Behaviour Through Public Policy describes how these, and other nudges, can be applied to public policy.

Making Maximum Savings the Default

Residential customers accounted for about 70% of metered pressurized-irrigation deliveries in 2018, making household irrigation an important opportunity for reducing demand. 

During the summer of 2018, Spanish Fork partnered with Rachio to distribute the company’s evapotranspiration irrigation smart controllers to 953 households that applied to the program online. These Wi-Fi enabled devices were provided by the city and installed for free by certified irrigation specialists. The controllers adjust water use based on weather conditions (for example not irrigating during a rain event). Specialists also adjusted the timing of irrigation to lessen the impact of peak. Participants could opt out of this component.

A 2019 study by Brigham Young University compared metering data from 542 of the participating homes to 1,452 residences without smart controllers. 

This approach partly utilizes the defaults lever described in Nudge: The Final Edition and MINDSPACE: Influencing Behaviour Through Public Policy. Homeowners did have to apply to the program, but they did not have to research, buy, or configure anything to get optimal results. The opt-out for programmed watering allowed participants to retain a sense of control.

Utilizing Information as a Motivator

Spanish Fork encouraged greater buy-in through positive reinforcement. Rachio provides an app that tracks the smart irrigation controller’s performance, such as showing how less irrigation is used when rain provides what’s needed.

This furnishes what MINDSPACE: Influencing Behaviour Through Public Policy calls the “salience lever” — making previously invisible behavior visible changes how people relate to it. This is especially important because most households tend to assume that their resource use is already around average (based on research on electricity usage).

What Changed as a Result?

• Participating homes used 17% less pressurized irrigation water than the comparison group, a difference of about 4,500 gallons per household per month. The evaluation compared 542 homes with controllers against 1,452 homes without controllers.
• Spanish Fork estimated that the average water savings from every six participating homes could offset the demand associated with one additional home. With 953 controllers installed in the first year, this ratio suggests capacity equivalent to roughly 159 additional homes.
• The number of residential connections grew by 4%, but overall system usage had only a 1.2% increase.
• In its 2024 Water Conservation Plan, Spanish Fork reported total water use of 196 GPCD, which it described as 33% below the 2007 statewide average of 295 GPCD. That longer-term figure reflects multiple citywide conditions and conservation measures, not the controller program alone..

Why Reducing Friction Matters Most

Even consumers who are interested in conservation may not take the extra effort to research, purchase, and set up a free or discounted smart irrigation controller. But they are happy to get one if all the legwork is done for them, including professional programming.

How Information Reinforces Change

The Rachio app moved households from passive to active participants by showing results that would otherwise have been obscured. Seeing the positive results of their actions made participants feel better about themselves for taking part.

How To Do the Same

• Remove or lower every barrier. A free device with free installation combined with straightforward applications can nudge people to take action.
• Pre-configure for local conditions. Make the path of least resistance the path to the best conservation outcome.
• Preserve a sense of autonomy. Offer an opt-out for some components so homeowners don’t feel they are being forced to hand over irrigation system control.
• Give homeowners salient insights. The app’s usage data encourages greater interest, and seeing the success of their actions promotes a positive self image.

By The Numbers

• 953 — Homes that received free installed and programmed smart irrigation controllers
• 542 — Sub-set studied and compared to 1,452 homes without the controllers
• 2018 — Year the program was initiated (June-August)
• 4,500 — Average monthly pressurized-irrigation difference per participating household, compared with homes without controllers 
• 17% — Average reduction in pressurized irrigation use among participating homes, compared with homes without controllers
• $300,000 — Provided by two $150,000 grants from the Utah Department of Natural Resources and the Central Utah Water Conservancy District
• $30,000 — City operating budget (professional installers, vehicles, conservation staff)
• 4% — Growth in connections
• 1.2% — Reported increase in total water demand in 2018, while connections increased 4%

Sources

Spanish Fork Irrigation-Water Conservation Study (Paxton, et al. Department of Civil and Environmental Engineering, Ira A. Fulton College of Engineering and Technology, Brigham Young University, 2019)

“Spanish Fork: Adding Capacity for Peak Demand with Smart Irrigation” (WaterNow Alliance. 2019, updated 2021)

Water Conservation Plan 2024 (Spanish Fork City Public Works. 2014)

“Smart Controller Project” (Spanish Fork City Public Works, program landing page)

Nudge: Improving Decisions About Health, Wealth, and Happiness (Thaler, R.H. & Sunstein, C.R. 2008)

Nudge: The Final Edition (Thaler, R.H. & Sunstein, C.R. 2021)

MINDSPACE: Influencing Behaviour Through Public Policy (Dolan, P. et al. United Kingdom Institute for Government. 2010)

“Social Norms and Energy Conservation” (Allcott, H. Journal of Public Economics, 95(9–10), 1082–1095, 2011. Free copy hosted by UC Berkeley)

Spanish Fork: Pressurized Irrigation System Master Plan (Steven C. Jones. Hansen, Allen & Luce, Inc. 2012)

Utah’s Municipal & Industrial Water Conservation Plan: Investing In The Future (Utah Division of Water Resources. 2014)