The weather-based technologies in WaterSense labeled controllers adjust the irrigation system’s station run times based on plants’ watering needs rather than on a preset, fixed schedule. A WaterSense labeled controller automatically reduces the watering times or days when less water is needed, typically during the cooler months.
As outdoor temperatures increase or rainfall decreases, labeled controllers adjust irrigation systems’ watering run times or schedule to compensate for the fluctuation. They will automatically alter their irrigation schedules daily or weekly based on site-specific variables, such as soil type, sprinklers’ application rate, and local weather changes. WaterSense labeled controllers have the potential to save homeowners across the United States 110 billion gallons of water and roughly $410 million per year on utility bills by continually balancing plants’ changing requirements with environmental changes.
Source: Weather-Based Irrigation Controller Mini Report (https://www.epa.gov/sites/production/files/2017-01/documents/ws-products-minireport-irrigation-controllers.pdf)