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Sprinkler Irrigation

Scope

Minimize and right size irrigation for water efficiency.

  • Use pop-up sprinklers for turfgrass.
  • Use micro-irrigation system to water plants other than turfgrass.

Sprinkler irrigation refers to types of irrigation that use mechanical devices with nozzles (sprinklers) to distribute the water by converting water pressure to a high-velocity discharge stream or streams. 

The U.S. Environmental Protection Agency WaterSense program requires that sprinkler heads have a 4-inch or greater pop-up height and matched precipitation nozzles. Sprinkler irrigation shall not be used on strips of turfgrass less than 4 feet wide, nor on slopes in excess of 4 feet of horizontal run per 1 foot vertical rise (4:1). Ensure narrow strips of turfgrass (installed less than 4 feet wide) and steep slopes have micro-irrigation if they are irrigated.

See the Compliance Tab for related codes and standards requirements, and criteria to meet national programs such as DOE’s Zero Energy Ready Home program, ENERGY STAR Certified Homes, and Indoor airPLUS.

Description

There are different types of landscaping irrigation equipment. Sprinkler irrigation is best suited for watering turfgrass as it can be designed to distribute water evenly over uniformly planted areas of turfgrass.

Lawn sprinklers are aimed to efficiently water turfgrass.
Figure 1. Lawn sprinklers are aimed to efficiently water turfgrass.

The varied heights of shrubs, trees, and plant beds can obstruct spray from sprinkler heads.  Shrubs, trees, plant beds, and any other non-turf landscape can be watered most effectively using micro-irrigation. Micro-irrigation supplies water directly to plant roots, reducing overspray and runoff. Micro-irrigation works through the frequent application of small quantities of water on or below the soil surface as drops, tiny streams, or miniature spray through emitters or applicators placed along a water delivery line. Micro-irrigation encompasses a number of methods or concepts, such as bubbler, drip, trickle, mist, or spray and subsurface irrigation.

The EPA WaterSense specification requires that micro-irrigation includes emission devices that have flow rates less than 30 gallons per hour (113.6 liters per hour). WaterSense specifies that sprinkler heads should have a 4-inch or greater pop-up height, as they need a certain amount of clearance above the turfgrass to operate correctly. Taller risers are less likely to be blocked by growing grass between mowings.

Designing a system with matched precipitation nozzles is an important water efficiency concept. A sprinkler head’s precipitation rate is the speed at which water is applied to a specific area. When an installer designs an irrigation system for a landscape, sprinkler heads are installed to deliver enough water to cover the entire area of the landscape. When all of the sprinkler heads within the zone or system have the same (or very similar) precipitation rates, they are said to have “matched precipitation.” Designing a system with matched precipitation-rate heads or nozzles can save water by ensuring that all areas of the landscape are watered at the same rate. This is especially important when a landscape has sprinklers with varying coverage (for example, half-arc and quarter-arc sprinklers).

Sprinkler irrigation should not be used on strips less than 4 feet wide, because it is difficult to irrigate narrow strips efficiently without creating overspray. Sprinkler irrigation should not be installed on slopes in excess of 4 feet of horizontal run per 1 foot vertical rise (4:1) because the flow rates associated with sprinklers are often a source of runoff on steep slopes.

An irrigation system installer can match the precipitation rate of the sprinkler heads in the irrigation system by calculating the precipitation rates and manually pairing similar heads in the same zone. The installer can also ensure matched precipitation by installing nozzles throughout the zone from the same family of nozzles produced by the same manufacturer. For matched precipitation, sprinkler head spacing must be consistent, flow rates must be based on coverage, and the pipes need to deliver water at a uniform pressure to each head.

Ensuring Success

A certified irrigation professional will verify that sprinkler irrigation systems comply with the criteria in the specification. In addition, the certified irrigation professional will verify that the station or zone pressure based upon the emission device or product being used (spray head, rotor head) is within +/- 10% of manufacturer-recommended operating pressure. The certified irrigation professional will test this on a representative zone of the sprinkler irrigation system.

Climate

Minimize irrigation needs by designing climate-appropriate landscaping and selecting native and drought-tolerant plant species. Schedule watering to match local climate conditions. For example, irrigation watering is not typically needed in most U.S. climates in the fall, winter, and spring.

Training

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Compliance

The Compliance tab contains both program and code information. Code language is excerpted and summarized below. For exact code language, refer to the applicable code, which may require purchase from the publisher. While we continually update our database, links may have changed since posting. Please contact our webmaster if you find broken links.

Environmental Protection Agency (EPA) WaterSense® New Home Specification

The EPA WaterSense New Home Specification states:

4.2.8 Sprinkler irrigation - Sprinkler irrigation, other than as a component of a micro-irrigation system, shall not be used to water plantings other than maintained turfgrass. Sprinkler heads shall have a 4-inch or greater pop-up height and matched precipitation nozzles. Sprinkler irrigation shall not be used on strips of turfgrass less than 4 feet wide nor on slopes in excess of 4 feet of horizontal run per 1 foot vertical rise (4:1).

This Retrofit tab provides information that helps installers apply this “new home” guide to improvement projects for existing homes. This tab is organized with headings that mirror the new home tabs, such as “Scope,” “Description,” “Success,” etc. If there is no retrofit-specific information for a section, that heading is not included.

The measures described in this guide apply to both new and existing homes.

More Info.

Access to some references may require purchase from the publisher. While we continually update our database, links may have changed since posting. Please contact our webmaster if you find broken links.

Case Studies

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References and Resources*

  1. Author(s): U.S. Environmental Protection Agency
    Organization(s): EPA
    Publication Date: July, 2014

    Resource that provides WaterSense inspectors with guidance for verification of program requirements for water-efficient new homes under the U.S. Environmental Protection Agency’s (EPA’s) WaterSense program.

  2. Author(s): U.S. Environmental Protection Agency
    Organization(s): EPA
    Publication Date: July, 2014

    Resource to help builders better understand the WaterSense requirements for labeled homes and assist them in meeting the criteria so they can receive the label for their new construction.

  3. Author(s): U.S. Environmental Protection Agency
    Organization(s): EPA
    Publication Date: July, 2014

    Resource that provides a checklist of program criteria for water-efficient new homes under the U.S. Environmental Protection Agency’s (EPA’s) WaterSense program.

  4. Author(s): U.S. Environmental Protection Agency
    Organization(s): EPA
    Publication Date: July, 2014

    Resource that establishes the criteria for water-efficient new homes under the U.S. Environmental Protection Agency’s (EPA’s) WaterSense program.

  5. Author(s): EPA
    Organization(s): U.S. Environmental Protection Agency
    Publication Date: June, 2017

    Resource that provides a directory of individuals that have sucessfully completed all requirements of at least one WaterSense labeled professional certification program.

Contributors to this Guide

The following authors and organizations contributed to the content in this Guide.

Last Updated: 06/30/2017