Innovative Irrigation: Underground Sprinkler Systems Evolve

Advances in technology mean that new underground irrigation systems can help you not only to keep your lawn green but also to keep more green in your wallet. New irrigation systems are more precise, and their components now are less expensive.

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Manufacturers of irrigation systems and components recently faced the double pressures of a tough economy and environmental concerns about using water for landscaping. But that doesn’t mean that there’s been a drought of efforts to advance their products. You’ll find that innovation has surged in consumer landscape irrigation systems to bring about more precise watering. That means that you can reduce your water bills.

PRESSURE POINT. The goal of installing an irrigation system, of course, is to cover your watering needs without wasting water. The “silent water wasters” are systems that have too much pressure—a common problem, says Brent Mecham of Irrigation Association, which is an industry trade organization. Environmental Protection Agency says the most common household water pressure is about 60 pounds per square inch (psi). However, the recommended operating pressure for fixed-spray sprinkler heads is 30 psi. The new breed of residential sprinkler heads have built-in pressure-regulating technology that reduces water pressure and keeps you from wasting water. (Rotating sprinkler heads operate best at 45–50 psi and typically don’t have the pressure-regulating feature.)

Six years ago, such technology was economically feasible only for large commercial installations, such as golf courses. But as water supplies have dwindled and water costs have risen, consumers’ and water authorities’ calls for responsible use of water have increased. When a fixed-spray sprinkler operates at 45–50 psi, instead of the optimal 30 psi, more water is pushed out of the head than is needed, according to Mecham. That’s wasted water, because excessive pressure causes the water to mist or create fog as it’s distributed, and that means that water evaporates instead of being absorbed by the plants. 

Sprinkler heads that typically are intended for residential use and that have pressure-regulating technology cost as much as $23, which is $4–$11 more than versions that don’t regulate pressure cost. But they can pay for themselves quickly, depending on the cost of water in your particular area.

Manufacturers and industry experts claim that a reduction of 5 psi in excess water pressure that’s over 30 psi can result in a 6 percent to 8 percent savings in water. Ali Harivandi, who is a professor of environmental horticulture at University of California Cooperative Extension Service, agrees with that estimate. If you go to 30 psi from 60 psi, that translates into a 36 percent to 48 percent water savings annually for your irrigation system. Of course, how much of your annual water use—EPA says the average yearly U.S. residential water bill is $214—is budgeted for your landscape depends on your climate and your landscape. 

An added advantage of the pressure-regulated sprinkler heads is that they eliminate the variance of flow throughout your entire system, which is a problem that conventional sprinkler heads don’t address. In other words, the flow and thus the sprinkling remains as constant at the beginning near to the home, as at the edge of your yard.

SAVING GREEN. If you haven’t looked at underground irrigation systems in the past 2 years, you’ll notice that prices are down—particularly for the controllers and the monitors that measure how much water that an irrigation system delivers and when. For example, 6 years ago, it would have cost you about $450 to get a system that had a controller that was paired with an on-site weather monitor (also called a weather station or a sensor) that received data from U.S. weather stations and adjusted your watering accordingly. You now can buy a controller-monitor combination that provides on-site weather information for as little as $165.

But what’s better is that the need to pay a monthly subscription fee so your irrigation controller could receive weather information has been superseded by sensor technology that measures local conditions and gives that information to the controller to activate watering. Consequently, we don’t know of any residential irrigation systems now that require a monthly subscription service for weather.

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