Smart irrigation is not a new concept for the green building community. Several types of technologies are mentioned within the International Green Construction Code (IgCC) and IAPMO Green supplement, as well as within programs such as the EPA’s WaterSense New Homes and LEED for Homes. Yet, only one smart irrigation product—the weather-based controller—has received widespread attention, mostly because it is the only irrigation technology that can qualify for the WaterSense label.
Brent Mecham, industry development director for the Irrigation Association, says that is something that needs to change if we are ever going to truly curtail outdoor water use. Mecham says there are actually four key technologies that should already be on every builder’s spec sheet:
• Weather-based (or climate-based) controllers: These controllers use weather data such as sunshine, temperature, and wind to help determine plant water requirements;
• Soil-moisture sensors: Often described as “electronic roots,” these sensors measure the moisture content in the soil to help mediate irrigation usage;
• Rain sensors: A device designed to interrupt a scheduled cycle of an automatic irrigation system controller when a certain amount of rainfall has occurred; and
• Pressure-regulating sprinklers: Manufactured sprinklers that regulate pressure to the nozzle over a range of inlet pressures.
According to Mecham, research has shown that each of these smart irrigation products has the potential to offer at least 20% in water savings, and in some cases, even more. A University of Florida study, for example, found that Florida homeowners could achieve up to a 44% water savings if they used a rain sensor. Interestingly enough, state law requires that any person who purchases and installs an automatic landscape irrigation system must install a rain sensor. Sadly, that same study estimated that only 25% of Florida homeowners are following the law and installing rain sensors.
Pressure-regulating sprinklers are another overlooked technology and actually fix an installation flaw found in most outdoor irrigation systems. “Many plumbers think that more pressure is better, but many irrigation systems are designed to work under lower pressure,” Mecham explains. “Spray heads only need to work at 30 psi, but we find many are working at 45 to 50 psi. If they were at 30 psi, it would be a about a 20% water reduction in the amount of water applied by the sprinkler, and the sprinkler will actually perform better. By having pressure-regulating sprinklers, even though there might be a lot of pressure coming in, it regulates the pressure to match the needs of the nozzle.”
Mecham believes that if every homeowner installed one smart irrigation product, we could see a 20% to 25% reduction in water use for maintaining the landscape. However, he is careful to point out that doesn’t mean we will be conserving water, but, more accurately, will be freeing it up for a different use. “We know the population isn’t going to stop growing and the demand isn’t going to go away,” he explains. “All of these products are mapped to improve irrigation efficiency, and one of the outcomes of irrigation efficiency often will be a reduction in the amount of water being used. This will be a vehicle to stretch the urban water supply to help meet all the demand.”
So what will it take to get these products into the marketplace? Mecham says a good place to start is to make all of them eligible for the WaterSense label. “The label is one of those marketing devices that makes it important,” Mecham says. “It would change the marketplace. Manufacturers would be ecstatic. In the end, water providers would be ecstatic. And the real winner would be the consumer.”
The holdup, Mecham believes, is a lack of testing standards—the key word here being standards. The Smart Water Application Technologies (SWAT), a joint initiative between product manufacturers and water purveyors, has already created testing protocols for all four technologies—you can check out the protocols here—but they are not formal standards, which Mecham says has slowed down market acceptance.
When it comes down to it, the EPA and other code enforcement bureaus prefer standards because they bring more stakeholders into the conversation and leave less room for ambiguity or bias. “It makes it so much easier for the EPA to reference a consensus-based public standard,” Mecham notes. “They want definitive language that is enforceable.”
Take soil moisture sensors as an example. Although the EPA has confirmed to Vision 2020 that WaterSense is considering the technology, Mecham says the EPA and product manufacturers are at a standoff: The EPA wants more testing results before moving forward with a soil-moisture sensor requirement, but product manufacturers have already paid to have products tested to the SWAT protocol and don’t want to invest in more testing. If there were testing standards in place, Mecham says everyone would be on the same page.
The good news is that testing standards are in the works. According to Mecham, SWAT is working with the American Society of Agricultural and Biological Engineers (ASABE) to start the standard process for both weather-based controllers and soil-moisture sensors. Rain sensors are on the horizon for a standard to be developed by International Code Council (ICC), but the timeline has not been established. Pressure-regulating sprinklers are already being considered by the ASABE/ICC Landscape Irrigation Sprinkler and Emitter Standard, which, once finalized, could easily be referenced by the EPA, says Mecham.
And there are more technologies—and standards—on the horizon. According to Mecham, high-performance nozzles are the next frontier for smart irrigation. In fact, SWAT is in the process of creating a testing protocol for these products, and Mecham expects a standard to soon follow. While high-performance nozzle technology is only a few years old, Mecham anticipates the marketplace to quickly gravitate to these products, even before the more established smart irrigation products. “The nozzles can easily replace existing nozzles and improve the performance of existing irrigation systems without the need for a major overhaul of the sprinkler system,” he explains.
In fact, several water utilities, especially in water-stressed locations, are offering incentives for the use of the nozzles, and many studies have shown that they do improve irrigation performance. But like the other smart irrigation technologies, Mecham still thinks a high-performance nozzle standard is necessary, especially since it is an emerging technology. “A standard testing protocol would provide a benchmark to be achieved for many of the new nozzles being engineered and manufactured for use,” he says.
Looking ahead, Mecham would like to see testing standards in place for all five technologies by 2015, which he thinks will help push these technologies through the WaterSense program and into more homes. However, Mecham says it will be important for the industry to create standards that focus on the future and leave room for innovation. “We don’t want to write a products standard or test standard that would actually inhibit innovation,” he says. “We want to write ones that would accommodate it. That, to me, is the real challenge.”