Avoiding the absurd scenario of running irrigation sprinklers during a rainstorm can be achieved through weather-based irrigation controllers, but there could be soil conditions where the sun might be shining and the landscaping still doesn’t need more water. Addressing the latter scenario requires soil moisture-based irrigation controls, also known as soil moisture sensors (SMS). Both weather and soil moisture-based controllers have existed on the market for some time, and the EPA WaterSense label has been available for weather-based controllers, but only recently has EPA been able to release a draft WaterSense label for soil moisture-based controllers.
Back in May 2013, the EPA WaterSense program released a Notice of Intent to develop a specification for soil moisture-based control technology. In December 2017, WaterSense was still dealing with gaps in data that prevented finalization of a full performance test method for bypass soil moisture-based control technologies. Those hurdles have now been cleared.
The WaterSense SMS specification as the draft now stands will apply to systems that can measure soil moisture levels to allow or block a preset irrigation event, but will not apply to SMS systems that trigger irrigation events dynamically. It is intended for residential or commercial landscape irrigation systems, but will not apply to systems for agricultural irrigation.
The draft SMS specification is open for public comment until January 10, 2020. EPA anticipates the label will be final by summer 2020.
In addition to the irrigation controller specification, the WaterSense label is available for spray sprinkler bodies.
Naomi Millán is senior editor of Building Operating Management.
