Quick Links for Technologies

• Energy-Efficient Products
• New Technologies
• Renewable Energy
• Distributed Energy Resources / Combined Heat & Power
• Operations & Maintenance
• Sustainable Design & Operations
• Industrial Facilities
• Laboratories for the 21st Century

Printable Version

BMP #5 - Water-Efficient Irrigation

Background

Some experts estimate that more than 50 percent of commercial and residential irrigation water is wasted due to evaporation, wind, poor management, and/or improper system design, installation, or maintenance. For optimal irrigation system performance, water efficiency should be considered from the inception of the system's design, through the installation, followed by consistent management and maintenance.

An important efficiency concept associated with irrigation systems is distribution uniformity, or how evenly water is applied over the landscape. Many times extra water is applied because the system is not distributing water in a uniform manner. When water isn't applied evenly, the landscape is watered to keep the driest spot green, grossly over irrigating other areas. This issue can be addressed through a number of measures discussed below.

Once the irrigation system hardware is operating in an efficient manner, it is important to consider the irrigation schedule, which dictates the amount and timing of the water applied. Water needs change with the seasons; so should your irrigation schedule. Many landscapes are watered at the same level all year, adding unnecessary water for months at a time. Over-watering can cause more damage to plant materials than under-watering and can damage streets, curbs, other paving and building foundations.

Whether installing a new irrigation system or retrofitting an old one, there are many options to help you improve its water efficiency. Most importantly, the person(s) responsible for the irrigation system should have training in proper system installation, maintenance, and management and work to maintain a current understanding of water-efficient irrigation practices and technologies. Work with your irrigation professional to increase your water efficiency outdoors.

For more information on this and other FEMP Water Efficiency Best Management Practices (BMPs), please see the resources section.

Operation and Maintenance Options

• Recommend existing contractors become familiar with water-efficient irrigation practices through partnerships, classes, seminars, and/or published guidance documents. Refer them to:
  • The Environmental Protection Agency's WaterSense program (visit the web site) to learn about becoming a WaterSense irrigation partner. WaterSense partners with irrigation professionals who are certified through programs that emphasize water efficiency.
  • Locally offered courses or seminars on water-efficient irrigation practices (check with your water utility or local junior colleges for availability)
  • Best management practices and guidance documents. Many local cooperative extensions and irrigation trade associations provide best management practice and guidance documents online.
• When hiring a vendor, inquire about the water efficiency knowledge of their personnel. Request demonstration of practices that promote efficient irrigation. EPA's WaterSense program can help you locate irrigation professionals in your area that have demonstrated knowledge in water-efficient irrigation. For more information and a list of WaterSense irrigation partners in your area, visit the EPA web site.
• Periodically review all irrigation service agreements to incorporate a high priority for water efficiency. Consider the following options:
  • Incorporate a water budget, which can be used as a performance standard for water use. A vendor will calculate your water needs and use that information to plan an irrigation schedule to meet those needs.
  • Require a full audit of your irrigation system every three years by a qualified auditor, such as a WaterSense partner. This process is an in-depth assessment of your system and its performance to verify proper scheduling and to expose growing deficiencies from changes or growth of landscape, or an aging system as well as opportunities to employ new technologies.
• Request vendors to include in their maintenance programs, immediate reporting and repair of problems as they arise and also require regular, periodic maintenance routines as part of the overall irrigation maintenance program.
• Install an irrigation meter (sometimes known as a "deduct meter") to measure the amount of water applied to the landscape. Some water utilities offer an interruptible rate for the service or will provide a credit to the sewer charges. Your maintenance vendor should keep a record of all irrigation water use as part of its maintenance program.
• Verify that the irrigation schedule is appropriate for climate, soil conditions, plant materials, grading, and season.
  • Change your schedule based upon changing weather conditions and as part of regular, periodic maintenance. Require your maintenance vendor and/or Auditor to deliver options for automating schedule changes based on changing weather conditions.
  • Certain soil types or steep slopes may increase the chance of surface runoff. Irrigation events may need to be broken up into multiple applications depending on landscape conditions. This is commonly known as "cycle & soak" methodology. Ask your maintenance vendor to assemble and implement such schedule parameters as necessary. If currently installed irrigation controller(s) is/are not capable of such programming, replace it/them with current technology.
  • Generally, it is better to water deeply and less frequently than to water lightly and often. A deep, less frequent schedule encourages deep roots resulting in healthy plants. As part of the overall maintenance program submission by your vendor, ask your vendor to produce and implement a program that takes into account the optimal water window and other scheduling requirements that relate to the actual landscape being maintained.
  • In addition to a full audit of your system every few years, periodically monitor your system for effectiveness throughout the year. As part of the overall maintenance program, ask your vendor to produce and implement a program that makes sure certain sprinkler components are placed and adjusted so that they will water the cultivated plants, not the pavement. Verify that irrigation system pressure is within manufacturer specifications. To help ensure consistent uniformity, require that replacement equipment is compatible with existing equipment.
• Always attach shut-off nozzles to handheld hoses.

Retrofit Options

• Replace your existing irrigation system controller with a more advanced control system that waters plants only when they need it. There are many available technologies that use weather or soil moisture information to schedule irrigation according to plant needs. Below are a few options to discuss with your service provider, an auditor or consultant/designer (detailed product information can be found in the following document (PDF 2.8 MB) Download Adobe Reader):
  • Weather Based Irrigation Control: Products come in the form of an irrigation controller, or a device that can be added to an existing controller. They use real-time or historical weather information, along with landscape parameters entered by the vendor, to schedule or allow for irrigation when plants need water.
  • Soil Moisture Based Irrigation Control: Products come in the form of devices inserted into the soil to measure moisture. They can be connected to an existing controller or add-on device, enabling irrigation when the plants need water.
  • Complete Central Control Systems: Products utilize demand-based control and enable a Water Manager to centrally operate and manage multiple irrigation systems at multiple locations using various means of communication.
• Consider retrofitting a portion of your trees, shrubs or plant beds with low-flow, low-volume irrigation, also called micro-irrigation or drip irrigation. Many plant beds do not require the spray heads traditionally used to water turf areas. Drip irrigation can be more efficient in part due to slow and direct water application to plant root zones, minimizing evaporation and runoff.
• Increase the efficiency of the system's sprinkler heads. Sprinklers with a fine mist are susceptible to water waste from wind drift. Also, some sprinklers don't apply water evenly over the landscape. Many times, existing sprinkler heads can be exchanged with more efficient heads designed to minimize water lost to wind and distribute water in a more uniform manner.
• Install rain sensing technology on your system to prevent irrigation from taking place during periods of sufficient moisture. Many cities, and some states, require rain sensing technology by law. Check with your state or city on relevant local laws.
• Install wind-sensing technology to interrupt irrigation cycles in the presence of significant wind.
• Install freeze-sensing technology to prevent irrigation during freeze conditions.

Replacement Options

• When installing a new system hire an irrigation design company that has a background in designing water-efficient systems, such as one that employs WaterSense partners. Also ensure that the installation and maintenance vendor has a background in water efficiency. For more information and a list of WaterSense irrigation partners in your area, visit the EPA web site.
• Upon completion of new irrigation systems, audit the irrigation system using a qualified irrigation auditor, such as a WaterSense partner, to determine if baseline efficiencies are compatible with design intent and to make certain minor adjustment recommendations as needed.
• Recommend that your system be designed, installed, and maintained according to irrigation best management practices, published by local cooperative extensions and irrigation or landscape trade associations. Following industry best management practices will help your irrigation contractor address efficient and water conserving techniques from design inception through installation and proper maintenance. For information related to the most widely known irrigation best management practices, go to http://www.irrigation.org/.
• Design your system for maximum water application uniformity (distribution uniformity). Discuss the following with your designer:
  • No direct distribution of water over impermeable surfaces or non-target areas.
  • Maximize sprinkler distribution uniformity by following manufacturer recommendations for head spacing. Consider necessary spacing reductions to compensate for prevailing wind.
  • Create irrigation hydrozones by grouping turf and plants with similar water needs. Also consider varying soil conditions, sun/shade/wind exposure, slope and other site specifics that may impact watering needs.
• Consider the installation of the following components for optimal water efficiency:
  • Drip/micro irrigation for all areas suitable for such technology.
  • Install check valves in all sprinklers to retain water in lateral pipes between cycles.
  • Demand based irrigation controls (i.e., weather or sensor based controls)
  • Rain, freeze, and wind sensors to interrupt irrigation during weather conditions that are unfavorable.
  • Flow rate monitoring equipment which can interrupt irrigation if excess flow is detected. (i.e., caused by broken pipes, fittings, nozzles, emitters sprinklers, etc.)
• Use alternative sources of water, as discussed in BMP #14, where environmentally appropriate and local regulations allow.

Water-Efficient Irrigation Resources

Some of the following documents are available as Adobe Acrobat PDFs. Download Adobe Reader.

Air Force Civil Engineer Support Agency. Air Force Water Conservation Guidebook, May 2002.

Arizona Municipal Water Users Association. Facility Manager's Guide to Water Management, Version 2.3 March 2003.

EPA's WaterSense Program.

General Services Administration. Water Management: A Comprehensive Approach for Facility Managers.

Military Handbook: Water Conservation. MIL-HDBK-1165. April 1997. (PDF 572 KB)

New Mexico Office of the State Engineer. A Water Conservation Guide for Commercial, Institutional, and Industrial Users, July 1999. (PDF 2.2 MB)

North Carolina Department of Environment and Natural Resources. North Carolina Water Efficiency Manual for Commercial, Industrial, and Institutional Facilities, 1998. (PDF 2.0 MB)

The Irrigation Association.

• "Landscape Irrigation Scheduling and Water Management" (out for peer review)
• "Recommended Audit Guidelines" (PDF 84 KB)
• "Turf and Landscape Best Management Practices" (PDF 341 KB)

U.S. Department of the Interior. Bureau of Reclamation. Reclamation: Managing Water in the West: Weather and Soil Moisture Based Landscape Irrigation Scheduling Devices, August 2007. (PDF 2.8 MB)

Vickers, Amy. Handbook of Water Use and Conservation. WaterPlow Press. Amherst. 2001.