WaterSense® Draft Specification for Soil Moisture-Based Irrigation
Control Technologies Public Meeting Summary
WaterSense® Draft Specification for Soil Moisture-Based Irrigation
Control Technologies Public Meeting Summary
November 20, 2019, 1:00 to 4:00 p.m. Eastern
Meeting Summary
The U.S. Environmental Protection Agency's (EPA's) WaterSense program released a draft
specification for soil moisture-based irrigation control technologies, also called soil moisture
sensors (SMSs), on November 7, 2019. The EPA organized this meeting with stakeholders as
part of the specification development process. The purpose of the webinar was to review the
WaterSense® Draft Specification for Soil Moisture-Based Irrigation Control Technologies and to
discuss stakeholder questions and comments.
The PowerPoint slides from this presentation can be reviewed on the WaterSense website at:
https://www.epa.gov/watersense/soil-moisture-based-control-technologies. A full list of the
attendees and a list of presenters are provided in Appendix A. The presentation discussion and
participant questions and comments are summarized below.
1.	Introduction
Stephanie Tanner, the EPA WaterSense program's Lead Engineer, welcomed everyone to the
meeting, clarified how to use the webinar software, and reviewed the meeting agenda and
objectives. Ms. Tanner provided an overview of WaterSense, a voluntary program that labels
water-efficient, high-performing products, including the program's history and the typical
WaterSense specification development process. WaterSense interacts with industry and other
stakeholders, such as standards committees and utilities, during this process. She detailed the
criteria the program uses for product evaluation and labeling. Through 2018, the WaterSense
program has helped consumers and businesses save 3.4 trillion gallons of water and $84.2
billion in water and energy bills.
2.	SMS Background
Julius Duncan of the EPA, defined the product category, summarized the research WaterSense
has conducted on SMSs dating back to 2007, and explained how this product can reduce
irrigation water waste, as well as and how it differs from other weather-based irrigation control
technologies. He described the EPA's history of collaborating with industry on test method
development and performance testing. WaterSense has actively participated in the development
of the recently published American Society of Agricultural and Biological Engineers (ASABE)
draft standard X633 Testing Protocol for Landscape Soil Moisture-Based Control Technologies
(ASABEX633). This standard provides a test method for examining the performance of SMSs
to sense moisture in the soil and inhibit an irrigation event when the moisture exceeds a pre-set
threshold. The EPA intends to require SMSs to be tested in accordance with this test method,
once the standard is final, in order to earn the WaterSense label. Mr. Duncan reviewed in detail
the various components of the test method described by the standard, including testing in
various soil types and salinity levels, at varying water depletion levels, and under freezing
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WaterSense® Draft Specification for Soil Moisture-Based Irrigation
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conditions. He explained that the University of Florida conducted performance testing using
ASABE X633. Mr. Duncan also noted that ASABE is accepting public comment on this standard
until December 2, 2019 and encouraged stakeholders to provide comments directly to ASABE.
Participant Questions
Are different types of soils used in the layers of soil for testing? Mr. Duncan responded that
different soil types are only used between different test boxes. Ms. Tanner clarifier that one box
will have fine soil and the second box will have coarse soil, but these types of soils are not
mixed between boxes. The standard details the soil recipes required for testing.
What is the purpose of the layers? Ms. Tanner explained that the soil and SMSs are packed into
the test boxes in a layered procedure, described in ASABE X633, ensuring that the soil is
packed tightly and uniformly around the SMSs for the test.
3. SMS Draft Specification: Scope
Mr. Duncan reviewed the definitions and terminology the EPA has crafted to define the scope
of this product category for the purposes of the draft specification, which were based on those
included in ASABEX633. The draft standard scope covers two types of products, soil moisture
content sensor controllers and soil water potential sensor controllers. The EPA crafted its
product definition to cover both of these technologies. Mr. Duncan described these
technologies and their components, including the sensor mechanism and the interface device.
The EPA has also developed three definitions for the draft specification that align with terms
used in the WaterSense® Specification for Weather-Based Irrigation Controllers (WBICs):
"stand-alone controllers," and "add-on and plug-in devices." Mr. Duncan clarified how these
terms apply to SMSs and defined the overall scope of the draft specification, clarifying which
types of products are included and excluded. He discussed the inclusion of products that enable
or disable an irrigation event based on readings from an SMS, while on-demand SMSs, which
initiate irrigation events based on a pre-set window of soil moisture levels, are excluded.
Mr. Duncan asked the audience a series of questions:
•	Based on what has been presented, is the proposed scope appropriate?
•	Specifically, is it appropriate to exclude on-demand type products? Did the EPA define
them accurately?
•	Should the EPA not limit the technology to soil water content sensor controllers or soil
water potential controllers? Are there other product types on the market?
Participant Questions and Comments
Please comment upon the weather-based irrigation controller definitions for irrigation adequacy
and irrigation excess versus the SMS definitions for water depletion levels and field capacity
levels. Please explain how these may be consistent. Ms. Tanner explained that these terms are
not interchangeable nor applicable among the product types, as they function very differently.
The EPA intends to make these specifications consistent through the packaging, labeling, and
supplemental capability requirements for certification.
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WaterSense® Draft Specification for Soil Moisture-Based Irrigation
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How did you define "event" as in the interruption of an "irrigation event"? Ms. Tanner explained
that many irrigation systems run on a scheduled irrigation program, and the SMS will
communicate the soil water content at the time a scheduled irrigation event should occur and
enable or disable that event as needed. Based on the moisture level that is present in the soil,
the SMS will or will not allow the irrigation schedule to continue.
Can we adjust the moisture or water content in the soil, or is this preset by the manufacturer?
Ms. Tanner explained that the moisture level is determined by what is actually present in the
soil. Most SMSs are intended to be conditioned in the soil onsite. The pre-set moisture levels
can be set by the user, but some models set this level automatically based on programming.
Joanna Kind of Eastern Research Group, Inc. (ERG), clarified that, if the threshold is set
automatically by the product, the user can override these threshold values.
Will there be testing developed for on-demand SMSs in the future? Ms. Tanner responded that
the EPA would like on-demand testing to be developed in future, but the technology currently
lacks a test method. The ASABE X633 development committee decided in 2013 that these
products would be tested separately, so the EPA limited the scope of the draft specification to
match the scope of the draft ASABEX633 standard. Tom Penning of Irrometer Company, Inc.,
added that ASABE's original intent was to develop a test method for on-demand SMS
technologies under the ASABE standard, X627 Weather-based Landscape Irrigation Control
Systems (ASABE X627). Thus, there is a path for these products to become part of the
standard process and be tested similarly to WBICs. Ms. Tanner briefly explained the history of
standard development related to WBICs and SMSs and ultimate split between the ASABE X627
and X633 standards committees. She noted the EPA is supportive of this process and hopes
there will be a way to accelerate development of a standard for on-demand SMSs.
Can you please define "irrigation event"? My interpretation of the specification is that there must
be a pre-defined irrigation schedule where watering can be inhibited based on soil moisture
content. It is not clear if an event shall be inhibited only at the start, or at any time during the
event. It is also not clear if the event shall not be inhibited once started. I think the goal is to
inhibit at any time during the event. Ms. Kind responded that products on the market currently
fall under one or the other of these categories (they can either inhibit an irrigation event at the
start or during the event), and the WaterSense draft specification is intended to apply to both
technologies. She suggested perhaps the EPA can include clarifying language in the final
I'm of the perspective that [on-demand technologies] should [be included in the specification].
Otherwise, you begin to negatively impact manufacturers' ability to innovate. A way to do that is
to include both those products that inhibit irrigation as well as generate irrigation events based
on moisture content. I don't think this seems like a significant change to the specification; if you
generate irrigation events based on moisture content, that seems appropriate. Then, if you
deem it necessary, you can develop constraints when applied to generated irrigation schedules.
For example, implement a constraint to not water on Tuesdays, even if the soil moisture content
is sufficiently low. This could be described as a constraint to go along with these generative
schedules. Ms. Tanner responded that later in the presentation she would discuss performance
criteria and supplemental capabilities included in the draft specification. However, one of these
capability requirements is for SMSs to work within a water utility's watering restrictions.
Typically, these are programmed into the base controller or stand-alone controller, including
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WaterSense® Draft Specification for Soil Moisture-Based Irrigation
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restrictions on watering certain days of the week. Ms. Tanner explained that the current issue
regarding on-demand technologies is the lack of a test method. The respondent noted he
believed developing a test method would be possible. Ms. Tanner noted that the current bypass
SMS test method took 13 years to develop and said she hopes that the lessons learned during
the bypass SMS test method development process would accelerate the on-demand test
method development process. She noted the EPA would be open to this process going forward
and is always interested in more technologies being labeled and supporting innovation in
industry to aid consumers.
Am I correct in assuming that you are excluding wireless SMSs that require a controller
interface from being in this program? Ms. Tanner responded that the specification includes
both wireless and wired sensor models that connect to base or stand-alone controllers. She
noted she would discuss this further in the presentation.
I have a question on the definition of an event. Many would define an irrigation program as a
series of events. The program criteria describe the program, schedule, or sequence itself as an
event, and this would be interrupted by the SMS. Ms. Tanner responded that the specification
intended a single event to be interrupted. She gave an example of a schedule planning irrigation
every Wednesday at a certain time; that specific scheduled event would be interrupted by the
SMS. The next Wednesday, the SMS would make the same evaluation. A new decision is made
every time the system is supposed to irrigate. The commenter noted that most controllers come
on at a scheduled start time and then run a series of stations or valves. Each of these stations
or valves would be an "irrigation event." The commenter said that they believe the intention is to
interrupt the beginning of that series of events, not to interrupt each individual event. Ms. Tanner
clarified that, generally yes, this is the intention and noted this description could vary depending
on the complexity of a given irrigation system and how many zones are equipped with SMSs.
Ms. Kind suggested respondents could submit clarifying language and definitions on this issue
in their written comments.
I'm a little confused by the definition for on-demand SMS. It says "enable" irrigation, and I think it
should be "allow" irrigation. How do (on-demand SMSs) differ from the scenario we just
discussed? Shouldn't these be included? Ms. Tanner explained that bypass SMSs are only
programmed with one soil moisture threshold, and on-demand SMSs have two of these
programmed levels. Another attendee clarified that the set of zones is referred to as a cycle of
zones—one event for all zones.
Will the SMS controller interrupt an irrigation event during the irrigation, or only prior to the start
of the irrigation event? Ms. Kind explained that there are different products available on the
market that operate both ways; some SMSs inhibit only prior to the start of the event, and some
will interrupt during the event. There is nothing in the specification to test the difference between
the two, so the user would need to evaluate which they prefer.
Who can we talk to about a test method for on-demand controllers? Ms. Tanner responded that
Brent Mecham of the Irrigation Association (IA) is head of the ASABEX627 standard
committee. She also noted that WaterSense will be attending the IA show in December 2019, in
Las Vegas, Nevada, and would be willing to meet with Mr. Mecham and manufacturers to
discuss how to restart standard development for on-demand technologies in the IA Resource
Center in the exhibit hall.
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WaterSense® Draft Specification for Soil Moisture-Based Irrigation
Control Technologies Public Meeting Summary
Can you elaborate on how utilities can restrict irrigation? Is there a universal software that can
over-ride different systems from various manufacturers? Ms. Tanner explained that some
products use signal-based cloud controllers; there has been some movement on the part of
utilities to have access to the data, but this is not widespread. Overall, most utilities will
recommend a schedule, and it is the responsibility of the homeowner to comply. Some utilities
enforce these restrictions.
4. SMS Draft Specification: Performance Criteria
Ms. Kind described the performance testing study conducted by the University of Florida under
a grant from the Metropolitan Water District of Southern California under their Innovation
Conservation Program (ICP). Four models of SMSs that comprise the majority of the market
were tested with the draft ASABE X633 test method. She noted the raw data will soon be made
available on the ICP website, and a summary report of the WaterSense analysis for this
specification is currently available on the WaterSense website at:
Three replicates of each of the four brands were tested in two soil media, at three depletion
levels and two salinities. WaterSense used the resulting data to establish the performance
criteria and to identify test method modifications for the purposes of this draft specification. The
EPA sought to evaluate whether all the test conditions were required and whether any of the
test results differed across different salinity and soil combinations. Statistical analysis helped the
EPA determine that these test conditions did not lead to statistically significant differences in the
test results. Thus, the EPA modified the test conditions to greatly reduce the burden on testing
laboratories. Ms. Kind described the research and evaluation process the EPA used to develop
these modifications and how these modifications reduce overall burden.
Ms. Kind explained the performance criteria included in the draft specification and justification
for inclusion. They include requirements related to functionality, precision (relative average
deviation [RAD]), ability to sense a change in soil moisture, and function after a freeze.
Participant Questions and Comments
Will there be one RAD value per SMS? Or will there be three RAD values, one each for 20
percent, 40 percent, and 60 percent? Ms. Kind explained there will be one RAD value for each
product, which is the average of those three RAD values at different depletion levels.
What is "field season"? Ms. Kind explained that term is intended to refer to the irrigation season.
It is the EPA's understanding that some SMSs need to be reconditioned after each freeze or
winter season.
Will WaterSense provide a spreadsheet to handle the details of the calculations? Ms. Kind
noted that a spreadsheet for calculations has been developed and distributed to the licensed
certifying bodies (LCBs) for all currently labeled irrigation products, and the EPA plans to do the
same for SMSs.
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Is the product tested while frozen to determine if it prohibits irrigation? Ms. Kind explained that
the product is not tested while frozen. The product is frozen, but then must return to the pre-test
temperature before being tested.
5. SMS Draft Specification: Supplemental Capability Requirements
Ms. Kind explained that the EPA intended to align this list of supplemental capability
requirements with those included in the WaterSense WBIC final specification. The original list in
the WBIC specification was developed through a working group with manufacturers and utilities.
She also noted that very few comments were submitted related to this list when the EPA
solicited feedback as part of its specification review process for the WBIC specification this past
year. This led the EPA to believe that this list of requirements is working successfully for
stakeholders. She also explained that the EPA hopes to promote WBICs and SMSs together as
"smart" irrigation control technologies and therefore aims to make the specifications as
consistent as possible
Ms. Kind explained that these requirements must be able to be met through programming and
functionalities included on either the stand-alone controller, or the add-on or plug-in device
paired with the compatible base controller. She walked through each of the requirements on the
list and the reasoning behind the EPA's inclusion of each.
Participant Questions and Comments
With regards to the note about loss of connection from the sensor mechanism, is the connection
in question between the controller and the add-on device, or loss of connection between the
sensor and the add-on? Ms. Kind explained that the supplemental requirements apply to either
a singular product (stand-alone controller) or to two pieces joined together (the base controller
and the add-on or plug-in device). If it is a stand-alone controller, then the connection in
question is between the sensor mechanism and the controller itself. If it is an add-on or plug-in
device, the connection lost would be between the sensor mechanism and the interface device.
Ms. Kind noted that some interface devices include red signal lights to indicate when the signal
has been lost.
For RAD equation, are there nine observations (three sensors by three boxes) ? Is there one
mean value (x bar) per each soil depletion? For clarity, consider defining "n" in the specification,
since it would always be the same and controlled by the test method. Ms. Tanner responded
that it is nine observations. Ms. Kind noted there is a mean value for each soil depletion and
suggested submitting a written clarification.
This concept of pairing the base controller with the add-on or plug-in device is new. It was not
discussed in the committee. It certainly makes sense for testing; however, the original intent
was for these devices to be easily used with homeowners' existing systems. This seems to now
be requiring them to replace their entire control system. There are some of these requirements
with which I'm not sure if any controllers on the market comply. These add-on devices are
simple switches, so if they lose communication to the controller, then the switch is just
constantly open. A wireless connection may be able to indicate it has lost communication, but a
simple switch won't be able to recognize this loss of signal. Ms. Tanner responded that an add-
on or plug-in device is designed to update, or make "smart," a base controller, such as a clock
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timer with some supplemental requirements. Generally, she said, WaterSense does not find
these add-on or plug-in devices have all of these capabilities, which is why the specification
requires them to be paired with a controller that does have them. This is to provide utilities some
level of assurance that systems in place have some minimal level of water-efficient functionality,
even if the communication connection is lost. The EPA realizes there is a cost and burden to
this, but WBIC manufacturers have been doing this for 9 years, have navigated it successfully,
and it has resulted in utilities rebating to their products that are not stand-alone products
(meaning add-on and plug-in devices).
It seems inappropriate to require a "rainfall" device as a supplementary requirement, since the
SMS itself is a "rainfall" device. Ms. Tanner clarified that the supplemental capability
requirements do not require a rainfall device to be attached, simply that it has the ability to
attach to one. However, it is the EPA's understanding that SMSs often connect to WBICs in the
same spot that a rainfall device would attach, so this requirement will necessitate some
discussion with industry to refine. The EPA agrees an SMS is similar to a rainfall device. Ms.
Kind added that the EPA is seeking direct feedback on the list of supplemental capability
requirements to identify these issues. Comments could be submitted that recommend adding,
modifying, or removing requirements from this list for the final specification.
Controllers switched to manual mode will not irrigate automatically, so there is no point in
automatically returning to some other mode. Ms. Tanner explained that the intent of the
requirement is to not have them switch back to manual mode, but rather for them to default to
the "smart" technology.
Are the test labs only to verify the supplemental requirements by review of the feature, or by
actual physical testing? Ms. Tanner said labs will review the that the features are present; but
they are not physically tested.
For add-on devices, especially if they connect to rainfall detectors, there is only the presence or
absence of rainfall. So how can one determine loss of communication? Ms. Tanner said that the
concern is whether the controller is receiving information from the SMS. On a plug-in device,
this indicator can be on the interface device, or on a stand-alone controller, it would be
integrated into the system. If that is not how these products function or that functionality is not
available, then this should be submitted in written comments and discussed with industry in
future. The EPA intends this requirement to apply to the SMS, not a secondary rainfall device
that may be present in the system. Ms. Kind added that the reasoning behind this requirement
comes from typical manufacturer instructions to program systems to irrigate every day. If that
signal is lost, the user should be informed, so if the system reverts to its original everyday
watering schedule, the user would be able to recognize and correct it. The EPA is open to other
methods by which this problem can be resolved.
The requirement to be "capable of allowing manual operation and automatically return to soil
moisture mode" could be interpreted a couple ways. Many affordable products on the market
are not going to meet this requirement because they have a physical hardware switch to bypass
interrupt devices to allow for things like testing and winterization. If this is allowed to stand, it
would force the consumer into a higher price category of controllers. I think we really should re-
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WaterSense® Draft Specification for Soil Moisture-Based Irrigation
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think this requirement; I couldn't support this. Ms. Kind requested these comments be submitted
in writing and the EPA will consider them.
6.	SMS Draft Specification: Packaging and Product Documentation Requirements
Ms. Tanner described the current definitions developed for WBICs (e.g., stand-alone, plug-in,
and add-on devices) and how the EPA has incorporated them into the draft SMS specification.
The EPA's intention with packaging and documentation requirements is to ensure that when
customers purchase WaterSense labeled products, they get the products they are expecting,
and efficient models are easy to identify. In the past, utilities expressed concern over products
operating in non-water-efficient modes. The packaging and product documentation
requirements reflect these needs of consumers and utility partners.
All products must come with instructions that tell the buyer how to use the product in the water-
efficient mode. All of the instructions required for product set-up and programming must be
included in the package or online, as this is how LCBs will obtain instructions for setting up the
product for testing. Labs are not permitted to request clarification or additional direction from the
manufacturer for testing.
Plug-in and add-on devices do not need to be sold with the base controller; these products are
intended to upgrade older or basic technology a user may already own. Documentation needs
to describe which base controllers this device is compatible with, and packaging must state this
device is only WaterSense labeled when paired with a base controller from this list. It must be
clear that this label is conditional on it being paired with an approved base controller.
7.	SMS Draft Specification: Testing Configuration and Compatible Base Controller
Ms. Tanner described the criteria used in initial testing of devices paired with base controllers.
She summarized recent improvements made to the WaterSense Product Search Tool, located
on the website here: https://lookforwatersense.epa.gov/. Ms. Tanner performed a live
demonstration of how to use the Product Search Tool to find WaterSense labeled WBICs and
their compatible paired products.
Ms. Tanner explained the intention behind these requirements is to ensure consistency with the
WBIC specification. This testing configuration serves as the basis for determining what the
controller compatibility is and how to ensure all these supplemental capability requirements are
met. Initial testing requires the base controller to be tested with the add-on or plug-in device,
and this combined unit is what is evaluated related to the supplemental capability requirements.
Beyond initial testing, manufacturers are encouraged to work with LCBs to identify what other
base controllers may be able to be added to their certification file.
Participant Comments
[Responding to a previous comment on reverting to manual mode] This is not a requirement that
the ET controller has to meet. Ms. Tanner responded that it is. Supplemental capabilities
included in the draft SMS specification are taken directly from the list of WBIC supplemental
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WaterSense® Draft Specification for Soil Moisture-Based Irrigation
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It would seem to me a feature set of required controller capabilities would be easier than this
thing with potentially thousands of compatible controllers. Ms. Tanner explained that it is
WaterSense policy not to label retrofit devices. She acknowledged that this system can be
tedious, but there are ample numbers of base controllers listed under the WBIC listing, so this
should not be an unreasonable burden for SMS manufacturers. It also increases the level of
confidence that utilities and other stakeholders have in WaterSense labeled products. Ms. Kind
added that by listing the base controllers, it relieves the responsibility from the user to determine
if the product they purchased has all the stipulated features.
8.	SMS Draft Specification: Certification and Labeling
Ms. Tanner gave an overview of the WaterSense certification system and encouraged
manufacturers that are not already program partners to file their partnership agreements now.
Taking care of this paperwork ahead of time helps prevent a backlog during the rollout of the
final specification. She recommended interested stakeholders review the Product Certification
System, located online at: https://www.epa.gov/sites/production/files/2017-02/documents/ws-
certification-product-svstem-v2.1.pdf. She briefly summarized the product sampling and
conformity assessment LCBs will perform for testing.
Ms. Tanner then explained the labeling process and how it differs for stand-alone controllers
compared to add-on or plug-in devices. She also explained the two different program marks and
where they are allowed to be displayed on websites and product documentation and packaging.
She then also described the function of Product Notification Templates (PNTs) and how LCBs
use them to communicate product information to the program, which is then displayed on the
WaterSense website.
9.	Next Steps
Ms. Tanner directed the audience to submit their comments, both positive and negative, or any
additional information pertinent to the WaterSense® Draft Specification for Soil Moisture-Based
Irrigation Control Technologies, to watersense-products@erg.com by January 10, 2020. The
EPA has since extended this deadline to February 1, 2020.
Other questions regarding the WaterSense program can be directed via email to the
WaterSense Helpline (watersense@epa.gov) or by calling (866) WTR-SENS (987-7367). Ms.
Tanner announced that WaterSense intends to make the comments received on the draft
specification public by publishing a comment compilation document. The EPA will review all
comments provided and will consider them while developing a final specification, anticipated for
summer 2020.
Ms. Tanner also encouraged attendees to review and provide comments on ASABE X633 to
ASABE by December 2, 2020. She noted that stakeholders interested in reviewing the standard
will need to obtain a copy from ASABE.
She completed the meeting by announcing that the EPA will be giving the same presentation: at
an information session at the IA Show in Las Vegas, Nevada, December 5 from 10 a.m. to
11:00 a.m. Pacific Time (the location can be found in the conference program). Any notes and
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WaterSense® Draft Specification for Soil Moisture-Based Irrigation
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comments received at the IA session will be appended to the summary document produced
from this webinar. The EPA will also be available for discussion at its table in the IA Resource
Center during the IA Show.
Ms. Tanner also directed the audience to review the draft specification, available on the
WaterSense website at: https://www.epa.gov/watersense/soil-moisture-based-control-
Participant Questions
Are there any accredited certification centers in Europe? Ms. Tanner responded no, however,
some LCBs do to some extent have an international presence. LCBs can test products in other
countries if they have an international presence. She recommended discussing this directly with
the LCB and looking up the LCBs currently performing irrigation testing for WaterSense with an
international presence and then infer which ones would also and have an international presence
and do the testing for SMSs.
What is the cost target for certification? Ms. Tanner responded that this is a market-based
decision between LCBs and manufacturers. But the EPA has spent a lot of time trying to reduce
the cost of testing that is required for the WaterSense program. Certification includes more than
just the product testing, and the cost of this process is between the LCB and manufacturer.
Ms. Tanner adjourned the meeting by thanking the audience for participating in the webinar and
encouraging attendees to submit written comments or stop by and see WaterSense staff at the
IA Show.
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WaterSense® Draft Specification for Soil Moisture-Based Irrigation
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Appendix A: Meeting Participants
Diganta Adhikari
Irrometer Company Inc.
Daniele Amistadi
Rain SPA
Maryellen Bell
HortScience Bartlett Consulting
Celine Benoit
Atlanta Regional Commission (Georgia)
Justin Burks
Santa Clara Valley Water District (California)
Dawn Calciano
City of Davis (California)
Maribel Campos
ICC-Evaluation Services (ES), LCC
Darik Chandler
Hunter Industries
Shirley Dewi
Holly Dickman
City of Hays (Kansas)
Michael Dukes
University of Florida
Johann Feller
Southern Nevada Water Authority
Mary Hattendorf
Northern Water (Colorado)
Erica Hinton
ANSI National Accreditation Board (ANAB)
Morgan Hopkins-Crawley
Aurora Water (Colorado)
Mark James
Brian Koblenz
Marc Kovach
Kovach Design Solutions, LLC
Elena Layugan
Upper San Gabriel Valley Municipal Water District (California)
Rodney Lynn
Forsyth County Water and Sewer Department (Georgia)
Cary McElhinney
U.S. Environmental Protection Agency (EPA) Region 5
Brent Mecham
Irrigation Association (IA)
Jayant Mehta
Jon Oen
David Evans and Associates
Eric Olson
City of Fort Collins (Colorado)
Kathleen Onorevole
Eastern Research Group, Inc. (ERG)
Tom Penning
Irrometer Company Inc.
Jackie Robbins
Krista Reger
Metropolitan Water District (California)
Clover Rogers
Jurupa Community Services District (California)
Sayetsi Sanchez
City of Woodland (California)
Larry Sarver
David Shoup
Hunter Industries
Jasmine Showers
City of Santa Barbara (California)
Sean Steffensen
California Energy Commission (CEC)
Jeff Tejral
Denver Water (Colorado)
Michael Temple
Molly Thistle
City of Pompano Beach Utilities Department (Florida)
Enrico Tresoldi
Rain SPA Home Irrigation
Daniela Urigwe
Energy Solutions
Robert Wanvestraut
South Florida Water Management District
Ron Wolfarth
Rain Bird Corporation
Veronica Blette
November 20, 2019

WaterSense® Draft Specification for Soil Moisture-Based Irrigation
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Julius Duncan
Stephanie Tanner
Crystal Jones
Joanna Kind
November 20, 2019

WaterSense® Draft Specification for Soil Moisture-Based Irrigation
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t'. t A
Apper 1 • ¦. , im , •• * --~~ons Discuss'-H^n-rterSense
Sessi	e Irrigation Association Show
WaterSense held an informational session at the Irrigation Association Show in Las Vegas
Nevada, December 5, 2019. The material presented during the session was identical to the
presentation delivered via webinar on November 20, 2019, as summarize above. The EPA is
presenting in this appendix the questions asked during the session to allow stakeholders who
were not able to attend to be informed of the topics discussed.
Q. Why not use local soils as a more realistic test? Why would cost (of materials, shipping, etc.)
be an issue to the EPA?
A. The ASABEX633 committee used real soil as opposed to engineered soil (i.e., media), for
several rounds of testing during the development of the test method. Finding soils that were
consistent with respect to soil composition (i.e., percentage of sand, silt, clay) was challenging
and was determined to be unsustainable over time. Additionally, shipping soil from one location
to another was extremely expensive.
Also, EPA does not do the actual certification testing. Testing for the label is done at third-party
certification bodies and paid for by the manufacturer. Reducing the cost for testing helps EPA
keep certification cost at a level that maximizes manufacturer partners participation in the
Q. If the sensors aren't tested in real soil, aren't users being expected to do the real-world
A. No, users will not be required to conduct real-world testing. Because real soils were used for
several rounds of ASABE X633 test method development, and results generated using real soils
were similar to those using engineered soils, the committee is confident that results in the media
are transferable to the field. Additionally, as part of the development of the draft specification,
EPA looked at water savings results from field studies using the SMSs that underwent
performance testing demonstrate that products that perform well on the laboratory test using
engineered soils will achieve water savings in the field.
Q. Is a wired connected to the interface device required?
A. The draft specification allows for the sensor mechanism to communicate with the device
either wirelessly or via a wire connected to the interface device.
Q. Why are the EPA modifications to the ASABE X633 test method not incorporated into the
A. The EPA modifications are not incorporated into the draft ASABE X633 test method for
several reasons. First, the timing of the draft specification and modifications made based on
performance testing came after the draft test method was developed and the draft standard was
in the process of being published. Second, some of the modifications could be specific to
WaterSense labeling and might not be desired for all entities interested in testing SMSs. For
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WaterSense® Draft Specification for Soil Moisture-Based Irrigation
Control Technologies Public Meeting Summary
example, with respect to the attachment of the SMS to a base controller for the power source, a
transformer could also be used if testing is conducted for purposes that don't require a base
controller. With respect to the reduction in the number of test media and salinity combinations,
despite performance test results generated by UF, utilities may want to conduct the test in soils
more similar to those in their region.
Q. Is there a requirement for the number of sensor mechanisms a product must be able to
communicate with?
A. The specification does not have a requirement regarding number of sensor mechanisms the
interface device must communicate with, but this information (i.e., maximum number of sensor
mechanisms the interface device can communicate with) will be displayed in the product search
tool on the WaterSense website.
Q. If an interface device communicates wirelessly with a base controller, how will the device be
powered during the test?
A. The EPA will discuss this question with the ASABEX633 committee and work with
stakeholders to determine the best path forward for these products.
Q. How will the test handle sensors that need to be calibrated before being installed in the soil?
A. The test method included in the draft ASABEX633 standard allows for calibration of SMSs
according to the manufacturer's instructions.
Q. One manufacturer expressed concern over the inclusion of the supplemental capability
requirements in the draft specification. Specifically, they are concerned these requirements
prevent SMSs from being used to retrofit the majority of base controllers installed in existing
irrigation systems. As a result, they said they will have to develop more expensive SMSs with
more features, or consumers will need to update their existing base controller at a greater
expense, eliminating the possibility of a retrofit.
A. The EPA understands this concern and is balancing it with the goal of promoting SMSs and
WBICs equally to utility partners. The list of supplemental capability requirements included in
the draft specification was developed by utilities and manufacturers during the WBIC
specification development process to ensure that, in addition to passing the performance test,
the controllers included additional features important to water efficiency (e.g. ability to comply
with watering restrictions, nonvolatile memory). This list of capabilities was recently reviewed by
WaterSense partners (both utilities and manufacturers) as part of WaterSense WBIC
specification review process, and none requested changes to this list, indicating to the EPA that
stakeholders are satisfied with labeled products that have now been on the market for 9 years.
Additionally, the EPA brought up the list of base controllers that have been identified to be
compatible with WBIC add-on and plug-in devices. These products are currently listed on the
WaterSense Product Search Tool and many will also be compatible with add-on or plug-in
Q. Are SMSs used in agricultural applications included in the scope?
November 20, 2019

WaterSense® Draft Specification for Soil Moisture-Based Irrigation
Control Technologies Public Meeting Summary
A. SMSs that are manufactured exclusively for agricultural use are excluded from the scope of
the draft specification. However, SMSs that can be used for both landscape irrigation and in the
agricultural applications are included in the scope of the draft specification.
Q. How will the LCBs test products that have both weather and SMS based control? Can these
earn the label?
A. These products can earn the WaterSense label. The specifications and associated
certifications for WBICs and SMSs will remain separate in the WaterSense program at this time.
LCBs will certify products that have the capability to operate in either weather-based mode or
soil moisture-based mode under each separate specification, meaning they will be tested and
certified to each specification should the manufacturer choose to do so. The EPA is aware that
there are controllers that use both weather and soil moisture simultaneously to schedule
irrigation. At this time, a test method is not available to sufficiently test this capability, so these
products will likely need to be tested and certified to meet one or both specifications, as decided
by the manufacturer. Product packaging and product literature shall clearly convey which
specification the product meets.
November 20, 2019