WaterSense-AWE Webinar Recap
Benefits of Soil Moisture
Sensors
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Alliance
Water
Efficiency
TODAY'S SPEAKERS
ORIGINAL DATE:
• Bill Christiansen - Alliance for Water Efficiency
MARCH 11, 2021
• Stephanie Tanner - EPA WaterSense

• Dr. Michael Dukes - The University of Florida
WaterSense Webinars
• Evelyn Reyes - San Gabriel Valley (California) Municipal
Webinar Recording on YouTube
Water District

WEBINAR SUMMARY
In the introduction, Mr. Christiansen provided an update on the Alliance for Water Efficiency's (AWE's)
Learning Landscapes Lessons. AWE has developed a collection of lessons aligned with Next Generation
Science Standards for grades 3 through 8, including new lessons to be added in 2021. The Learning
Landscapes Grant Program will be used to build new or improve existing outdoor educational spaces like
school gardens, educational landscapes on public/government property, botanical gardens, or other
community locations. The lessons are posted on the AWE website (https://www.home-water-
works.org/teachers).
Following that, Ms. Tanner went over the newest addition to
WaterSense labeled products, the Soil Moisture-Based
Irrigation Controller. Also referred to as Soil Moisture Sensors
(SMSs), these products save water by inhibiting an irrigation
event if moisture in the soil is determined to be adequate, so
plants don't need water. WaterSense worked with the ASABE
S633 committee to develop a test method that tests sensor
precision based on soil type, salinity, and water level. The
scope includes products that enable or disable an irrigation
event based on a soil moisture sensor mechanism, for
residential or commercial applications, wired and wireless
technologies, and stand-alone controllers and add-on or plug-in devices. WaterSense estimates savings
of 30 percent or 15,000 gallons of water annually in an average residential landscape.
FEATURED SPEAKER: DR. MICHAEL DUKES
The SMS consists of the sensor device that is buried in the soil and the interface device that connects to
the controller or timer. The timer is in control of the irrigation schedule and the information from the
sensor device is relayed to the interface device to allow or bypass an irrigation cycle. The sensor device
should be installed in an area of the landscape that would require the most frequent irrigation and be
buried in the active portion of the root zone, approximately 3 inches deep for turfgrass, but that can
depend on the type of plant material. Sensors must be calibrated after installation in the soil by saturating
the soil with water and allowing the device to run in calibration mode.
Case Studies
WaterSense Materials at
https://www.epa.gov/watersense
Find It. Flag It. Fix It: A Checklist for
Your Landscape
Brochure: It's Time to Start a
Sprinkler Spruce Up!
Case Study: Albuquerque
Apartments Realize Savings with
Rebate and Retrofits
PHONE (866) WTR-SENS (987-7367) WEBSITE www.epa.gov/watersense EMAIL watersense@epa.gov
*>EPA March 2021

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WaterSense-AWE Webinar Recap
Dr. Dukes presented on several research project completed by The University of Florida. Studies
included tests that compared the use of different SMS weekly schedules to plots that did not
include a sensor and how their performance impacted the quality of turfgrass plots. Those results
were also compared to plots that were under a lower irrigation threshold.
In a study in Pinellas County Homes, they compared landscapes with SMS, a rain sensor, and
education materials and found that the SMS group saved the most water. Afterwards a similar
study was performed with the use of reclaimed irrigation water where the SMS controllers also
reduced irrigation.
Do Smart Controllers save water?
Plot based studies often don't reflect the same results as out in the field, with reported water
savings of 42 to 68 percent. By performing home research studies, water savings were closer to
23 to 31 percent. A summary publication is available through the American Society of Agricultural
and Biological Engineers at https://elibrarv.asabe.orq/abstract.asp?aid=51812.
FEATURED SPEAKER: EVELYN REYES
San Gabriel Valley Municipal Water District provides 7 different rebates for indoor and outdoor products.
They established a rebate for SMS because in 2018 California established legislation for water
conservation and drought planning. The Water District developed a rebate to encourage the use of SMSs
in irrigation. Rebate guidelines are for residential customers only, sites at least 500 square feet, and the
total rebate amount should not exceed the cost of the device.
Lessons learned
Because SMSs are a fairly new technology, the district did not have as much participation as
expected, customers need a compatible irrigation system, and installation is not as easy.
SPEAKER QUESTIONS AND ANSWERS
Q: Do both ET controllers and SMS offer the same water savings?
A: Dr. Dukes answered that the savings could be dependent on the application. In a rainier climate, the
SMS may be better equipped to handle the schedule, but with additional technology in WBIC the
products offer similar potential.
Q: Did you find a reluctance by contractors to participate in the rebate?
A: Ms. Reyes answered that they did not experience any reluctance from contractors.
Q: How often is it necessary to calibrate the sensors?
A: Dr. Dukes answered that they only calibrated the sensors once and did not need to recalibrate
throughout the study. But in other areas of the country it may be necessary to calibrate during the spring
after the system has been frozen.
Q: What is being done to inform the typical gardener of the new technology?
A: Ms. Tanner answered that the WaterSense program has PCO programs that certify irrigation
professionals that are updated with the knowledge of the newest technologies, the Your Better Yard
campaign focuses on ideas for adding these products to your landscape, and product mini-reports with
more of the technical information about these products.
PHONE (866) WTR-SENS (987-7367) WEBSITE www.epa.gov/watersense EMAIL watersense@epa.gov
*>EPA March 2021

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