if - x,
WaterSense
at Work
Outdoor Water Use
5.2 Irrigation
Best Management Practices for
Commercial and institutional Facilities
*
EPA
WaterSense
November 2023
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WaterSenseฎ is a voluntary partnership program sponsored by the U.S. Environmental
Protection Agency (EPA) that seeks to protect the nation's water supply by transforming
the market for water-efficient products, services, and practices.
WaterSense at Work is a compilation of water efficiency best management practices
intended to help commercial and institutional facility owners and managers from multiple
sectors understand and better manage their water use. It provides guidance to help
establish an effective facility water management program and identify projects and
practices that can reduce facility water use.
An overview of the sections in WaterSense at Work is below. This document, covering
water efficiency for irrigation systems and equipment, is part of Section 5: Outdoor
Water Use. The complete list of best management practices is available at
www.epa.gov/watersense/best-management-practices. WaterSense has also developed
worksheets to assist with water management planning and case studies that highlight
successful water efficiency efforts of building owners and facility managers throughout
the country, available atwww.epa.gov/watersense/commercial-buildings.
Section 1. Getting Started With Water Management
Section 2. Water Use Monitoring
Section 3. Sanitary Fixtures and Equipment
Section 4. Commercial Kitchen Equipment
Section 5. Outdoor Water Use
Section 6. Mechanical Systems
Section 7. Laboratory and Medical Equipment
Section 8. Onsite Alternative Water Sources
EPA 832-F-23-003
Office of Water
U.S. Environmental Protection Agency
November 2023
This document is one section from WaterSense at Work: Best Management Practices for Commercial and
Institutional Facilities (EPA-832-F-23-003). Other sections can be downloaded from
www.epa.gov/watersense/hest-management-practices. Sections will be reviewed and periodically updated
to reflect new information. The work was supported under contract 68HERC20D0026 with Eastern Research
Group, Inc. (ERG).
November 2023
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Outdoor Water Use
4
Irrigation
EPA
WaterSense
Overview
The efficiency of a landscape irrigation system is determined by many factors, including
human, mechanical, and environmental components. Implementing mechanisms and
practices that increase an irrigation system's efficiency could reduce a property's outdoor
water use by more than 50 percent. In landscapes around the country, a significant
amount of water is lost from evaporation, wind, or runoff due to improper irrigation system
design, installation, or operation and maintenance. Eliminating this waste involves trained
professionals, appropriate irrigation schedules, and efficient technologies. Additionally,
the landscape itself (e.g., plant palette, soil type, etc.) plays a role in irrigation water use
and provides the potential for additional water savings. See WaterSense at Work Section
5.1: Landscaping at www.epa.gov/watersense/best-management-practices for more
details.
One of the most important concepts affecting irrigation system efficiency is how evenly
water is applied to the landscape. Figure 1 a below illustrates uniform application. Figure
1 b below shows uneven application, where some parts of the root zone may be
underwatered or overwatered. Without uniform application, the landscape is often
watered to keep the driest spot green, resulting in overwatering of other areas. Head-to-
head coverage, illustrated in Figure 2 on the next page, is intended to apply water as
uniformly as possible. For maximum efficiency, sprinklers should be located so that water
distributed from one sprinkler reaches adjacent sprinklers.
Figure 1. Examples of Good (a) and Poor (b) Uniformity1
a.
Application depth
b.
Under watering -
Application depth'
Application depth-
1 Florida Water Star. Distribution (application) uniformity, https://floririawaterstar.com/technical-
manual/irrigation-criteria/distribution/.
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WaterSense at Work
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Figure 2. Example of Head-to-Head Coverage Spray Pattern2
13.5 H
13.5
I I
In addition to considering how evenly water is applied, it is equally important to consider
the irrigation schedule, which dictates the amount and timing of the water applied.
Landscape water needs change with the seasons, and so should the irrigation schedule.
Many landscapes are irrigated at the same rate all year, which can lead to unnecessary
water use. Overwatering can damage plants more than underwatering; it can also lead to
runoff that can pollute waterways as it runs over streets, curbs, other pavement, and
damage building foundations.
The right components and proper design, installation, operation, and maintenance of an
irrigation system play a significant role in landscape water efficiency. To capitalize on the
water savings potential from more water-efficient irrigation technologies, the EPA has
published specifications for three irrigation products to earn the WaterSense label:
WaterSense Specification for Spray Sprinkler Bodies3
WaterSense Specification for Weather-Based Irrigation Controllers4
WaterSense Specification for Soil Moisture-Based Irrigation Controllers5
2 Florida Water Star. Sprinkler spacing, https://floridawaterstar.com/technical.-manual/irrigation-
criteria/distrihution/sprinkler-spacing/.
3 U.S. Environmental Protection Agency's (EPA's) WaterSense program. Spray Sprinkler Bodies.
www.eoa.gov/watersense/spray-sprinkler-bodies.
4 EPA's WaterSense program. Weather-Based Irrigation Controllers, www.epa.gov/watersense/weather-
based-irrigation-controllers.
5 EPA's WaterSense program. Soil Moisture-Based Irrigation Controllers, www.epa.gov/watersense/soil-
moisture-based-irrigation-controllers.
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WaterSense at Work
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The list below provides more information on irrigation technologies and how WaterSense
labeled irrigation products can help reduce water use.
WaterSense labeled spray sprinkler bodies
adjust the incoming water pressure to match
the optimal pressure of the sprinkler nozzles
(e.g., 30 pounds per square inch [psi] [207
kilopascals or kPa]). The spray sprinkler body is
the exterior shell that connects the irrigation
system piping and the spray nozzle that applies
water on the landscape. In some cases, the
irrigation system pressure is higher than
recommended for the sprinkler nozzle, resulting
in excessive flow rates, misting, fogging, and
uneven coverage. WaterSense labeled spray
sprinkler bodies regulate water pressure and
reduce water waste by providing a constant flow
at the sprinkler nozzle. They also generate the
appropriate amount of water spray and coverage
for more uniform distribution of water across the
landscape. For incoming water pressure above
60 psi (414 kPa), pressure-regulating spray
sprinkler bodies can reduce water use from spray
sprinklers by more than 20 percent.6
High-efficiency sprinkler nozzles distribute water in multiple streams and
trajectories, resulting in larger droplets that are less likely to be affected by wind.
These features can increase the efficiency of the sprinkler distribution. Existing
spray sprinklers can be retrofitted with high-efficiency nozzles, which can be
screwed into the sprinkler body. Sprinkler nozzles should also have a matched
precipitation rate, meaning that all nozzles in a particular zone apply the same
amount of water across a given area per hour.7 WaterSense is considering labeling
high-efficiency sprinkler nozzles. For more information on the specification
development process, refer to www.epa.gov/watersense/spray-sprinkler-nozzles.
WaterSense labeled irrigation controllers8 apply water only when needed based
on weather data, soil moisture, or other onsite conditions. These controllers can be
stand-alone controllers or add-on or plug-in devices that can be used in
conjunction with an existing clock-based controller (i.e., an irrigation timer) to help
6 EPA's WaterSense program. September 21, 2017. WaterSense Specification for Spray Sprinkler Bodies
Supporting Statement, www.epa.gov/sites/riefault/files/2017-09/riocuments/ws-proriucts-support-
statement-ssh.pdf.
7 Florida Water Star. Matched precipitation. https://fLorirtawaterstar.com/technicaL-manuaL/irrigation-
criteria/distribution/matched-precipitation/.
8 EPA's WaterSense program. WaterSense LabeLed ControLLers. www.epa.gov/watersense/watersense-
LabeLeri-controLLers.
Cross-section of spray sprinkler
body and nozzle
Image courtesy of Irrigation
Association Smart Water
Application Technologies
Spray
-sprinkler
body
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WaterSense at Work
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it water more efficiently. Some models are app-based, providing the added
convenience of monitoring and controlling water use from mobile devices, whether
onsite or from afar. Properly installed WaterSense labeled irrigation controllers can
reduce irrigation water use by 15 to 30 percent. WaterSense currently has
specifications for two types of irrigation controllers to earn the label:
o Weather-based irrigation
controllers can make irrigation
schedule adjustments more
convenient and water-efficient
by using local weather data and
landscape conditions to tailor
the amount, frequency, and
timing of landscape watering. To
work effectively, these
controllers must be installed
and programmed properly,
accounting for facility-specific
landscape conditions and the
irrigation system installed.9
Weather-based irrigation controller
Photo courtesy of Rachio
o Soil moisture-based irrigation
controllers (commonly known
as soil moisture sensors, or
SMSs) effectively tailor irrigation
schedules to meet landscape
water needs based on direct
measurements of moisture in
the soil, which helps reduce
water waste and promote plant
health.10 SMSs include a sensor
mechanism that is inserted into
the soil and an interface device
that enables or disables an
irrigation event at preset or
selected soil water values.
Microirrigation is a highly efficient
method of application because it
directs water to plant roots at a low
flow rate, avoiding water lost to wind or
Soil moisture sensor (inset: sensor in ground)
Photos courtesy of Hunter Industries
Example of microirrigation: drip emitter
Photo courtesy of Rain Bird Corporation
9 EPA's WaterSense program. May 2020. Smart Watering With V\/eather-Based Irrigation Controllers.
www.epa.gov/sites/default/files/2020-05/documents/ws-products-irrigation-outdoor-wbic-mini-report.pdf.
10 EPA's WaterSense program. March 2021. Smart Watering With Soil Moisture-Based Irrigation Controllers.
www.epa.gov/sites/default/files/2021-04/documents/ws-outdoor-products-sms rnini-report.pdf.
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Adding Microirrigation to Your Services:
A Mini-Guide for Irrigation Professionals
runoff. Microirrigation delivers water directly
to the root zone of the plant, where it is
needed most. It disperses water slowly and
over a longer period of time so the water
infiltrates the soil, preventing runoff and
reducing evaporation. Microirrigation is
recommended for non-turf landscape areas
{e.g., plant beds, trees). This technology uses
between 20 to 50 percent less water than
conventional spray sprinkler systems.11
WaterSense also labels programs that assess and
certify irrigation professionals' competency in
irrigation system design, installation and
maintenance, and auditing;12 and publishes guides
focused on educating residents or property
managers about specific aspects of outdoor water
use, such as microirrigation.13 The suite of product specifications, labeled professional
certification programs, and technical guides is intended to address water use in irrigation
systems as a whole.
To date, there are no federal standards for water efficiency in irrigation products.
However, several states require that certain irrigation products meet WaterSense's
criteria.14 In addition, many water utilities offer rebates for WaterSense labeled or other
efficient irrigation products to encourage customers to install them where appropriate.
Use the WaterSense Rebate Finder at www.epa.gov/watersense/rebate-finder to find
current rebates for a particular location.
The key to saving irrigation water is to combine water-smart landscaping and efficient
irrigation practices with efficient technologies. Below are some tips for improving irrigation
system efficiency, including operation and maintenance, replacement, and retrofit
options. Additional details on many of these principles, practices, and technologies can
be found in the Irrigation Association's (lA's) guidance, Landscape Irrigation: Best
Management Practices.15
11 EPA's WaterSense program. May 2018. Adding Microirrigation to Your Services: A Mini-Guide for Irrigation
Professionals, www.epa.gov/watersense/microirrigation.
12 EPA's WaterSense program. Irrigation with a Pro. www.epa.gov/watersense/irrigation-pro.
13 EPA's WaterSense Program. Additional Outdoor Resources, www.ena.gov/watersense/additional-
outdoor-resources.
14 Appliance Standards Awareness Project. State Standards, https://applianoe-standards.org/states.
15 Irrigation Association (IA). May 2014. Landscape Irrigation: Best Management Practices.
www.irrigatiQn.oi-g/IA/Advocacy/Standards-Best-Practices/Landscape-lrrigation-
BMPs/IA/Advocacy/Landscape-lrrigation-BMPs.aspx.
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WaterSense at Work
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Operation, Maintenance, and User Education
A facility can consider several best management practices to optimize an irrigation
system's efficiency. These can include ensuring that irrigation professionals are properly
educated on water-efficient practices and technologies and that existing irrigation
systems are properly operated and maintained.
Irrigation Professional Education
Consider the following to ensure that irrigation professionals have a strong understanding
of the principles of water-efficient irrigation:
Ensure that existing professionals or staff managing the irrigation system become
familiar with water-efficient irrigation practices through partnerships, classes,
seminars, and/or published guidance documents. Encourage professionals or staff
managing the system to:
ฉ
FIND A PRO
o Become certified through a WaterSense labeled
irrigation professional certification program with an
emphasis on water efficiency.16
o Consult the local water utility, community colleges,
or agricultural services for courses or seminars on
water-efficient irrigation practices.
o Review technical guidance documents provided by
local cooperative extension services and irrigation
trade associations.
When hiring new irrigation professionals to work with the system, inquire whether
they have water efficiency certifications or specific training focused on efficient
irrigation, and look for irrigation professionals certified by WaterSense labeled
programs. Visit the WaterSense Find a Pro tool at www.epa.gov/watersense/find-
pro to find certified professionals in your area.
Irrigation System Operation
In addition to periodically reviewing all irrigation service agreements to emphasize the
operation of a water-efficient system, verify that the irrigation schedule is appropriate for
climate, soil conditions, plant materials, grading, and the season as described below:
Irrigation schedules should be updated based on changing weather conditions and
as part of regular maintenance. Require the irrigation professional and/or auditor to
deliver options for automating schedule changes based on changing weather
16 EPA's WaterSense program. Professional Certification. www.epa.gov/watersense/professional-
certification-Q.
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WaterSense at Work Irrigation
conditions. Installing and properly programming a WaterSense labeled controller
can provide this capability.
Certain soil types or steep slopes could increase the chance of surface runoff.
Irrigation events may need to be separated into multiple applications depending on
landscape conditions. This is commonly known as cycle and soak methodology. If
existing irrigation controller(s) are not capable of such programming, consider
installing more current technology.
It is generally better to apply water in larger volumes less frequently. This deep
watering approach encourages the growth of deep roots, resulting in healthy
plants. Note that soil type plays a role in creating this type of schedule and should
be taken into consideration.
Incorporate a water budget, which can be used as a performance standard for
water use. A budget provides a specified amount of water that should not be
exceeded when watering the landscape and can be compared to the property's
actual water use.
The Importance of Metering
Since outdoor water use can make up
a significant portion of a facility's total
water use, it is important to install a
dedicated water meter to measure
irrigation water use. Reading the meter
regularly can help facilities fully
understand their outdoor water use
trends, see the results of water
efficiency efforts, and quickly identify
leaks. For more information about
using water meters to manage facility
water use, refer to WaterSense at Work
Section 2.1: Metering and Submetering
at www.epa.gov/watersense/best-
management-practices.
Irrigation System Maintenance
Irrigation systems require regular maintenance to
ensure optimum performance. Consider the
following system maintenance tips:
Install a dedicated water meter for the
irrigation system to measure the amount of
water applied to the landscape. Some
water utilities offer an interruptible rate for
the service or will not apply sewer charges
to water used for irrigation. Have the
irrigation professional or staff managing the
system keep a record of trends in irrigation
water use as part of the maintenance
program.
Train facility staff and landscape
contractors to perform frequent site walks
of the irrigation system. Staff should look
for unexpected wet spots on sidewalks, in parking lots, and in landscaped areas
and report instances to building management. These wet spots could be a sign of
an underground irrigation line leak or improperly positioned or broken sprinkler
heads. For more detailed guidance on finding leaks, refer to the WaterSense Find It,
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WaterSense at Work
Irrigation
Flag It, Fix It Checklist17 or WaterSense at Work Section 2.2: Leak Detection and
Repair at www.epa.gov/watersense/best-management-practices.
Verify that irrigation system pressure is within manufacturer specifications.
Sprinkler nozzles typically operate optimally at a water pressure between 30 or 45
psi (207 or 310 kPa). Installing WaterSense labeled pressure-regulated spray
sprinkler bodies or a pressure-regulating valve on the whole system can help
sprinklers function more efficiently under high incoming pressures, which can
commonly exceed 60 psi (414 kPa).
Request that irrigation professionals or staff managing the system include
immediate reporting and repair of problems in maintenance programs, and require
regular maintenance routines as part of the overall irrigation maintenance program.
Require a full audit of the irrigation
system every three years by a qualified
irrigation auditor certified by a
WaterSense labeled program if
possible. The American National
Standards Institute (ANSI)/American
Society of Agricultural and Biological
Engineers (ASABE) Standard S626:
Landscape Irrigation System Uniformity
and Application Rate Testing provides
guidelines for conducting an irrigation
audit.18 A full audit should include an
in-depth assessment of the irrigation
system, its performance, and schedule.
In addition, the audit should expose
deficiencies that have occurred from
either system and/or landscape
changes. The audit is an opportunity to
identify appropriate new technologies
as well. Audits should evaluate the
uniformity of water applied across the
landscape. To help ensure uniformity,
replacement equipment should be
compatible with existing equipment
and manufacturer.
Improperly positioned irrigation sprinklers
spraying onto pavement
Leaking irrigation valve
17 EPA's WaterSense program. April 2020. Find It, Flag It, Fix It: A Checklist for Your Landscape.
www.epa.gov/sites/default/fiLes/2020-04/documents/ws-outdoor-landscaping-find-it-flag-it-audit-
checkList.pdf.
18 American National Standards Institute (ANSI)/American Society of Agricultural and Biological Engineers
(ASABE). ANSI/ASABE S626 Landscape Irrigation System Uniformity and Application Rate Testing.
https://elibrary.asabe.org/abstract.asp?aid=47429.
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Retrofit Options
If retrofitting an irrigation system, consider the following options to decrease landscape
water use.
Irrigation System Controllers and Sensors
An existing irrigation system can be optimized with the following retrofits to the controls or
components:
Replace existing irrigation system controllers with WaterSense labeled irrigation
controllers that water plants only when needed. There are many available models
using weather or soil moisture information to schedule irrigation according to plant
needs, WaterSense labeled weather-based and soil moisture-based irrigation
controllers can be purchased as standalone controllers, or they can upgrade an
existing clock-based controller as an add-on or plug-in device.
If not installing soil moisture-based irrigation controllers, consider installing rain-
sensing technology to prevent irrigation from taking place during periods of
sufficient rainfall. Note that many cities and some states require rain-sensing
technology by law. Check with the state or city on relevant mandates.
Consider installing other sensors to cut down on wasted water. For example, wind-
sensing technology interrupts irrigation cycles in the presence of significant wind.
Freeze-sensing technology prevents irrigation during freeze conditions. Flow rate
monitoring equipment can interrupt irrigation if excess flow is detected (e.g.,
caused by broken pipes, fittings, emitters, or sprinklers).
If managing a large property, consider installing central control systems that use
demand-based controls to enable a water manager to centrally operate and
manage multiple irrigation systems at multiple locations with various means of
communication.
Irrigation System Hardware
In addition to retrofitting the control system to
decrease water use, a facility can consider
retrofitting irrigation system hardware as
follows:
Consider retrofitting a portion of the
sprinklers that water trees, shrubs, or
plant beds with microirrigation.
Microirrigation is more appropriate than
traditional spray sprinklers for many
plant beds.
Microirrigation in shrub beds
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WaterSense at Work
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Consider exchanging existing sprinkler bodies with WaterSense labeled pressure-
regulated spray sprinkler bodies.
If sprinkler spacing will be changed, arrange sprinklers to provide head-to-head
coverage.
Replace traditional spray sprinkler nozzles with high-efficiency nozzles that have
matched precipitation rates, meaning that all nozzles in a particular zone apply the
same amount of water across a given area per hour.
Retrofit other water-using devices on the property to use water more efficiently. For
example, attach shut-off nozzles to handheld hoses to make sure water is going
directly to the plants rather than dripping on the ground.
Replacement Options
If replacing an irrigation system, there are
as many opportunities to increase its
efficiency during the phases of system
design and installation as there are during
system operation and maintenance. Hiring
qualified irrigation professionals and
ensuring a well-designed system are key
to achieving water savings from an
irrigation system replacement.
Qualified Irrigation Professionals
Select an irrigation installation and
maintenance professional who has been
certified by a WaterSense labeled program
or otherwise has experience in water
efficiency. Use WaterSense's Find a Pro
web page at
www.epa.gov/watersense/find-pro to find
a qualified local irrigation professional. In
addition, consider the following:
Ensure onsite staff are trained in
the maintenance and use of the
new system.
When a new irrigation system is installed, use a qualified irrigation auditor certified
by a WaterSense labeled program19 to ensure that the installed system's
Look for Irrigation Professionals Certified
Through a WaterSense Labeled Program
When a facility chooses to hire look for
irrigation professionals certified
through a WaterSense labeled
program, it ensures the irrigation MV vJO
professional is familiar with
water-efficient irrigation practices,
which can help reduce water use, save money,
and maintain healthy landscapes by
maximizing the efficiency of the irrigation
system. A facility can find certified irrigation
professionals to design, install, maintain,
repair, and/or audit irrigation systems using
WaterSense's Find a Pro tool at
www.epa.gov/watersense/find-pro. A facility
can encourage their existing irrigation
professional to get certified through a
WaterSense labeled program to improve their
aptitude in water-efficient irrigation best
practices by directing them to WaterSense's
website at
KVlVlVil^ IK HRtlVlVfS 11^ I Kir/J J f J ICKKi 1*11 rS LC
certification-O.
19 EPA's WaterSense program. Find a Pro. www.epa.gov/watersense/find-pro.
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performance meets the design intent. The auditor can make minor adjustment
recommendations as needed.
System Design Considerations
When replacing an irrigation system, recommend that the system be designed, installed,
and maintained according to technical guidance published by local cooperative
extensions or IA. Visit iA's website at
www.irrigation.org/IA/Resources/IA/Resources/Resources.aspx for further technical
guidance and information related to the most widely known irrigation best practices. In
addition, consider the following:
Design the system for maximum water application uniformity. Request that the
designer:
o Ensure that water is not distributed to impermeable surfaces or non-target
areas.
o Maximize irrigation uniformity by following manufacturer recommendations
for sprinkler spacing and design the system with head-to-head coverage.
Create irrigation hydrozones by placing plants with similar water needs together.
Also consider varying soil conditions, sun/shade/wind exposure, slope, and other
site specifics that could impact watering needs.
Consider installing the following components for optimal water efficiency:
o Microirrigation for all areas
suitable for such technology.
o High-efficiency sprinkler nozzles
and WaterSense labeled spray
sprinkler bodies for turf and other
areas that require spray irrigation.
o Check valves in all sprinklers to
retain water in lateral pipes
between cycles.
o WaterSense labeled irrigation
controllers.
o Rain, freeze, and wind sensors to interrupt irrigation during unfavorable
weather conditions.
o Flow rate monitoring equipment that can interrupt irrigation if excess flow is
detected.
Arrange for an irrigation system audit by a professional certified by a WaterSense
labeled program after installation to ensure the design intent was met and any
problems are repaired before the system goes into operation.
Rain sensor
Photo courtesy of Hunter Industries
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Use alternative sources of water (see WaterSense at Work Section 8: Onsite
Alternative Water Sources at www.epa.gov/watersense/best-management-
practices) where environmentally appropriate and local regulations allow. Keep in
mind that while alternative sources are an additional way to save water in a
landscape, improving efficiency should be the first step in a water conservation
project. Apply all relevant principles above to build the most efficient system
possible, and then consider using alternative sources.
Savings Potential
To evaluate both water and cost savings associated with irrigation system improvements,
it is important to first understand how much water is applied to the landscape. Dedicated
irrigation meters track irrigation water use and allow facilities to document actual savings.
Use these meters to measure water usage before and after irrigation upgrades. See
WaterSense at Work Section 2.1: Metering and Submetering at
www.epa.gov/watersense/best-management-practices for more information.
Savings from implementing any water-efficient technology depend on the operation of the
system as a whole, including the landscape and climate. As a result, actual water savings
are landscape-specific. Following are a few examples of anticipated savings, as well as
some examples of projects that realized savings from implementing water-efficient
technologies in the landscape. To view details of these projects and additional case
studies on water-efficient irrigation in a commercial setting, visit the WaterSense Case
Studies web page at www.epa.gov/watersense/case-studies.
The Oklahoma City Utilities Department retrofitted the irrigation system for
turfgrass in three roadway medians to include pressure-regulating spray sprinkler
bodies that met WaterSense criteria and high-efficiency nozzles. The project also
switched to using WaterSense labeled weather-based irrigation controllers. The
project reduced water use in the medians by 67 percent.20
The Resort at Pelican Hill in Newport Beach, California, installed WaterSense
labeled weather-based irrigation controllers on its property as part of a suite of
measures to increase water efficiency. The controllers accounted for most of the
18 percent water savings realized during the first year of the project.21
20 EPA's WaterSense program. "Oklahoma Makes Median Irrigation OK."
www.epa.gov/sites/iiefault/files/707Q-Q3/documents/ws-commerciaL-casestudy-okLahomacity-
medians.pdf.
21 EPA's WaterSense program. "CaLifornia GoLf Resort Hits HoLe in One With Outdoor Water Efficiency
Efforts." www.epa.gov/sites/defauLt/fiLes/2017-01/documents/ws-commerciaL-casestudy-peLican-hiLL.pdf.
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A field study of residential properties in Orange County, Florida, found that
residents with a soil moisture-based irrigation controller used 30 percent less
water for irrigation compared to residents with a regular clock-timed controller.22
A field study of single-family homes in Palm Harbor, Florida, found that homes with
a rain sensor used 14 percent less water than residences with a regular clock-
timed controller.23
Finally, because behavior can also play a role in outdoor water use, it is important to make
sure that staff who are responsible for landscaped areas understand the importance of
ensuring that irrigation equipment is working properly. If irrigation controllers are not
properly set or controls are overridden, the investments made to improve water efficiency
may not result in water savings.
Cost Savings
Multiple factors may influence cost savings associated with irrigation system
improvements. Many of these factors depend on the billing policies of the local water
utility.
Commercial buildings may be more likely to have utility-supplied water meters dedicated
for irrigation. If so, the water utility may not issue sewer bills for water used for irrigation.
The water rate (cost/unit of water) may also be different from the rate of the main potable
water meters serving the facility. Similarly, if utility-supplied reclaimed water is used for
irrigation, it may have a different rate than potable water. It is helpful to understand the
water rate for irrigation water, as this may influence whether a project is cost-effective.
Rebates and other incentives can also impact the net cost savings of a water efficiency
improvement project. Local water utilities may offer rebates to offset the cost of a
particular irrigation technology or portions of the entire project.24 "Pay for performance"
rebates may also be available, in which rebate value is determined by the volume of water
saved. These may be relevant for a larger project that addresses landscape transformation
and multiple components of the irrigation system.
22 Water Research Foundation. Smart Irrigation Controller Demonstration and Evaluation in Orange County,
Florida. www.waterrf.org/research/projects/smart-irrigation-controLLer-demonstration-and-evaLuation-
orange-county-fLorida.
23 HaLey, MeLissa B., and Dukes, MichaeL D. December 2009. Evaluation of Sensor Based Residential
Irrigation Water Application on Homes in Florida. Paper presented at InternationaL Irrigation Show in San
Antonio, TX, December 2-4,2009.
www.irrigation.org/IA/FiLeUpLoads/IA/Resources/TechnicaLPapers/2009/EvaLuationQfSensorBasedResidenti
aLlrrigationWaterAppLicationOnHomeslnFLorida.pdf.
24 EPA's WaterSense program. Rebate Finder, www.epa.gov/watersense/rebate-finder.
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Additional Resources
Alliance for Water Efficiency (AWE). Landscape, Irrigation, and Outdoor Water Use.
www.allianceforwaterefficiency.org/resources/outdoor.
Albuquerque Bernalillo County Water Utility Authority. Irrigation Efficiency Guide: Beautiful
Landscapes with Less Water, www.505outside.com/wp-
content/uploads/2022/10/Final ABCWUA-lrrigation-Guide REDUCED.pdf.
American National Standards Institute (ANSI)/ American Society of Agricultural and
Biological Engineers (ASABE). ANSI/ASABES626 Landscape Irrigation System Uniformity
and Application Rate Testing, https://elibrary.asabe.org/abstract.asp7aid-47429.
Austin Water, City of Austin Watershed Protection, Texas A&M Agrilife Extension. Earth-
Wise Guide to Irrigation.
www.austintexas.gov/sites/default/files/files/Watershed/growgreen/factsheets/irrigation.
pdf.
City of Bend. WaterWiseTips.org Irrigation Guide.
www.bendoregon.gov/home/showpublisheddocument/32238/636596544544830000.
EPA's WaterSense program. Irrigation with a Pro. www.epa.gov/watersense/irrigation-pro.
EPA's WaterSense program. Microirrigation. www.epa.gov/watersense/microirrigation.
EPA's WaterSense program. Product Search, www.epa.gov/watersense/product-search.
EPA's WaterSense program. Spray Sprinkler Bodies, www.epa.gov/watersense/spray-
sprinkler-bodies.
EPA's WaterSense program. Spray Sprinkler Nozzles, www.epa.gov/watersense/spray-
sprinkler-nozzles.
EPA's WaterSense program. Watering Tips, www.epa.gov/watersense/watering-tips.
EPA's WaterSense program. WaterSense Labeled Controllers.
www.epa.gov/watersense/watersense-labeled-controllers.
Florida Water Star. Irrigation system criteria, https://floridawaterstar.com/technical-
manual/irrigation-criteria/.
Irrigation Association. May 2014. Landscape Irrigation: Best Management Practices.
www.irrigation.org/IA/Advocacy/Standards-Best-Practices/Landscape-lrrigation-
BMPs/IA/Advocacy/Landscape-lrrigation-BMPs.aspx.
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Irrigation Association. Resources.
www.irrigation.org/IA/Resources/IA/Resources/Resources.aspx.
Water Use It Wisely. Saving Water Outdoors, https://wateruseitwisely.com/saving-water-
outdoors/lawn-watering-guide/.
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Disclaimer
This document was prepared as an account of work sponsored by the United States Government.
While this document is believed to contain correct information, neither the United States
Government nor any agency thereof, nor any of their employees, makes any warranty, express or
implied, or assumes any legal responsibility for the accuracy, completeness, or usefulness of any
information, apparatus, product, or process disclosed, or represents that its use would not
infringe privately owned rights. EPA hereby disclaims any liability for damages arising from the use
of the document, including, without limitation, direct, indirect, or consequential damages
including personal injury, property loss, loss of revenue, loss of profit, loss of opportunity, or other
loss. Reference herein to any specific commercial product, process, or service by its trade name,
trademark, manufacturer, or otherwise does not necessarily constitute nor imply its endorsement,
recommendation, or favoring by the United States Government nor any agency thereof. The views
and opinions of authors expressed herein do not necessarily state or reflect those of the United
States Government nor any agency thereof.
v>EPA
United States Environmental Protection Agency
(4204M)
EPA 832-F-23-003
November 2023
www.epa.gov/watersense
(866) WTR-SENS (987-7367)
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