One More Time: Recycled Water in Irrigation

As drinking water and ground water supplies dwindle, reclaimed water is water that works for irrigation. Treated municipal wastewater, reclaimed (or recycled) water is seeing increased use in landscape and turf applications throughout the country with great success.

With water a rapidly diminishing resource, using reclaimed water for nonpotable purposes such as irrigation makes perfect sense. "We’ve got to use what water we have," pointed out Larry Keesen, a professional irrigation consultant with Keesen Water Management, Denver, Colo. "They’re not going to make any more. It’s a finite quantity."

Reclaimed water works well for a range of irrigation applications since there is an abundance of this high quality, relatively low cost water available for use, according to David Davis, a professional irrigation consultant based in Rancho Cucamonga, Calif. "Across the country, water treatment plants are producing a tremendous amount of reclaimed water that they can’t get rid of," he said.

RECLAIMED WATER ON THE RISE. Reclaimed water is most commonly used in large-scale commercial irrigation applications such as golf courses, athletic fields and landscapes. This recycled resource is frequently relied upon in places where the drinking and ground water supply is limited or strained due to heavy demand, such as in the Southwest, Southeast and Western United States. In Southern California, for example, all streetscaping is irrigated with recycled water, according to Davis.

Because of increased liability, since reclaimed water isn’t as high quality as drinking water, reclaimed is less commonly used in residential situations, although use is on the increase. This is happening particularly in areas with rapidly expanding populations and, in turn, heightened demand for water. In the Southwest, for example, new housing developments are frequently set up to handle reclaimed water for irrigation purposes, Davis said.

In Florida, as well, reclaimed water use is frequently mandated in residential areas, said Michael Sidlovsky, president, Aqua-Matic Irrigation Systems, Naples, Fla. He noted that in Collier County, where his company is based, reclaimed water use has been mandated for at least a decade. In this part of Florida, water can be a scarce commodity, especially during the height of tourist season in the winter months, Sidlovsky said.

As the U.S. population continues to grow and water resources continue to diminish, there’s no doubt that reclaimed water use will continue to increase, according to irrigation experts. "As water resources become more scarce, if it’s not already, any large metropolitan area will have to consider using reclaimed water," pointed out Terry Little, a professional irrigation consultant based in Dallas, Texas. Given this fact, contractors should plan accordingly and get educated.

DO YOUR HOMEWORK. Reclaimed water is a highly regulated resource with a host of rules and regulations. Since there is no federal standard governing its use, these guidelines vary by region and state and meticulously dictate when, where and how much reclaimed water can be used. In some areas, for example, reclaimed water can’t be used next to a restaurant or an outside patio area, because of the close proximity to people.

Regulations also commonly dictate the level of quality reclaimed water must be for use in a particular application. "Landscape generally requires the highest quality because there are people around," according to Davis. "If it’s just a spray field with no public access, the grass can take poorer quality water."

In addition, a local water authority might specify what kind of plant material reclaimed water can be used on, which can present problems when retrofitting an existing system. "You might not have plants that are the best for this," said Davis, who has seen reclaimed water’s extra minerals damage trees and shrubs.

Overall, the best way for contractors to familiarize themselves with all rules and regulations regarding reclaimed water is to talk with their local water authorities and work from there, Davis advised.

While most regulations vary by water district, there are a few standard safety procedures when handling reclaimed water in an irrigation system. Safety is a significant issue since reclaimed water isn’t as pristine as regular drinking water. "The big thing is keeping people out of it," Davis said, noting that contractors should be overcautious when using reclaimed water and err on safety’s side.

One standard approach to handling reclaimed water safely is using purple system components to signify that this water is in use. Strategically placed signage is also a common safety measure employed with reclaimed water. "On most roadways and medians, when reclaimed water is used for irrigation, we use a lot of signage," Sidlovsky said.

Similarly, on office park projects he’s worked on, Keesen has put signs at all the entrances to indicate that reclaimed water is in use on that property. Otherwise, it could be a liability issue if someone tries to drink the water or kids play in it. Once again, however, safety precautions such as signage and purple components fall under the jurisdiction of landscape contractors’ local water authorities and should be handled accordingly.

GETTING STARTED. Not surprisingly, using reclaimed water requires careful installation. For one, a system must be flawlessly designed so that there is no run-off or overspray, the pressure is consistent and the overall system is as efficient as possible, according to Keesen. "Essentially, it’s all the basics of good irrigation design," he
pointed out.

On the other hand, if an existing system will be converted to handle reclaimed water, all the components must be changed out, Keesen said, advising contractors or an irrigation consultant to go in and evaluate such aspects as pressurization, flow rate and drainage. To retrofit, Keesen suggested using heads with check valves as much as possible and carefully documenting the existing backflow prevention device’s removal. "Once that disconnection is verified, they can come in and connect the system to the reclaimed water supply," he said.

Once a system has been retrofitted to accommodate reclaimed water, there’s no going back. "Once a line has recycled water in it, it is contaminated forever," Davis said. "It can’t be retrofitted for potable water."

Another key installation issue is figuring out how to store reclaimed water. The type of storage, such as open surface, elevated tank, underground or a direct system connection, largely depends on what application the water will be used for, according to Little. "With a golf course, which needs 1 million gallons of water a night, on-site storage is the way to go," he said. "With an athletic field, however, pressure isn’t as much of an issue, so direct piping would be fine."

Davis has seen a trend toward underground storage. Otherwise, "you can’t get the water when you need it," he observed.

In addition, Sidlovsky advised using the best filtration system possible at the connection point. "As well as the water is filtered as it comes out from the water treatment plant, there are still some particulates that manage to get through," he said. "If you filter before the water goes into the system, maintenance costs are a lot less."

POINTS TO PONDER. There is no shortage of issues to keep in mind when working with reclaimed water. For one, an irrigation system using reclaimed water requires diligent, ongoing maintenance and must be kept in the best possible working order, Davis said, noting that monitoring this kind of system compared to a more conventional one requires a more sophisticated approach. This includes using such monitoring tools as a weather station, to ensure that there is no drift from wind and that the system doesn’t run in the rain. Davis also recommended using a flow-monitoring device, so in case there is excess flow due to a leak, the whole system shuts down as a safety precaution.

If contractors are going to use reclaimed water in an irrigation system, they need to have a good line of communication with their local water authorities, to make sure they’re getting proper pressure exactly when they need it, advised John Swindle, landscape national manager, Flowtronex PSI Ltd., Dallas, Texas.

"Request upfront that they supply constant pressure," he said, noting that on many jobs he’s been involved with, the water authority doesn’t always understand how an irrigation system operates and what the specific pressure needs are. "They’re under the impression that it runs under the same flow all the time," he said.

Little observed that using reclaimed water with drip irrigation could possibly clog sprinkler heads. With lesser quality reclaimed water, algae problems, for example, can jam emitters and spray heads. On a golf course or in a park, however, this is less of an issue since larger nozzles are used, he said.

In addition, depending on where it is used in a landscape, reclaimed water can have a negative impact on particular types of plants that can’t handle the water’s additional salt and mineral levels. "You just can’t go out and spray reclaimed water on everything," Davis said.

Keesen noted that on landscape sites he’s worked on, salt levels in reclaimed water have killed certain types of evergreen trees, such as pine and spruce. "Trees that don’t drop their needles are more susceptible," he said. "The needles absorb the reclaimed water, and any additives in that kind of water can kill those trees."

Reclaimed water can have a beneficial impact, however, on the landscape. Keesen pointed out that in some cases, reclaimed water actually provides additional nutrients for turf.