For years, landscaping companies have installed and maintained time-based irrigation system controllers. But what if a monsoon swamps a section of the country? Most irrigation systems still water based on their internal timer. The fact that the turf they’re irrigating won’t need water for another week or so doesn’t enter the picture. As a result, the system wastes water and over-irrigates the lawn. But new technology, in the form of smart irrigation controllers, is changing that.

Their introduction is timely: New legislation in California, AB 1881, is setting higher landscape water conservation standards throughout the state by 2010. And other cities and states are considering similar legislation. With the new standards comes the requirement to use smarter irrigation controllers, and that means business for you. Residential and commercial property owners will rely on landscaping companies to install these systems to meet the new water conservation expectations and water budget allocations.

According to the Virginia-based Irrigation Association, a nonprofit organization focused on water conservation, “smart” sprinkler controllers use compact electronic control modules to reduce outdoor water use by monitoring and acting on pertinent information about site conditions such as moisture, rain, wind, slope, soil and plant type. Taken together, these conditions, act in a process known as evapotranspiration, or ET.

This is the process by which soil loses water through water evaporation and transpiration from plants. Ideally, to avoid irrigating too much or too little, you want to know 100 percent of all ET taking place in a plot of soil. However, knowledge of a lower percentage will still save your clients money.

According to Rob Starr, head of strategic technologies for Toro Irrigation, the most accurate way to receive precise ET data pertaining to the site is to have a real weather station on the property, like many golf courses do. But weather stations can cost $10,000 or more, and not many customers want to spend that kind of money. The next best – and most cost-effective – irrigation control method is an ET controller.

ET controllers work well when installed on residential and stand-alone commercial sites, but because this technology is new, there is some resistance now from customers. According to Tom Penning, president of ET controller manufacturer Irrometer, it’s a matter of cost-effectiveness. “A lot of residential clients might not be willing to spend the money for the controller or the signal fee each month, especially with homes changing hands every few years.”

In response, you have to explain the advantages of these systems to your customers. “An ET controller is going to save them money because it is conserving water,” says Aaron Hauck, electronics product manager for Nelson Turf. “Sites that have used ET controllers experience a healthier landscape because they are not over watering. With over watering, you can get fungus issues or you can push fertilizers past the root mass into the ground water.”

Controllers paint a complete moisture picture
According to Susan Basch, senior product manager at Rain Bird, economics, the price of water and the size of the area to be watered are the primary factors determining what type of ET controller you’ll want to use to irrigate a site. “For larger, more complex sites, the closer you can get to 100 percent ET, the better,” Basch says. “For smaller sites, 80 percent to 90 percent ET might be close enough.”