It doesn’t take an expert to tell that there’s a problem when you see broken pipes or water gushing into the street. It’s obvious that something is broken and needs to be fixed. But it does take an experienced person to examine a water bill and determine if there are better ways to reduce it and, at the same time, conserve water. That’s what an irrigation audit is designed to do.
Most clients want to conserve water. Some are motivated by ecological concerns. But let’s face it, many are motivated by money. They want their water bills reduced, and they don’t want to pay fines and surcharges when they get busted by the ‘water police’ for using too much. This is of real concern to owners and managers of large commercial sites, who use hundreds of thousands of gallons of water per year. When their bills get too high, or they’re told to cut their usage, that’s when they may ask for an audit.
Evaluating just how much water is being used on a landscape, and how effectively, is what a water audit can do. The word ‘audit’ is a scary one, bringing to mind the picture of a stern-looking IRS agent going over your tax returns with a magnifying glass. An irrigation audit might also cause a property owner to reach for the Xanax, if it reveals a need for some extensive and expensive repairs.
To reduce water usage, a formal audit may not always be necessary. You can also walk a site and make notes on what you see. This kind of audit is called an ‘evaluation.’ “Sometimes, problems are so obvious, they practically jump right out at you,” says Dave Wesolowski, founder and president of Sprinkler King in San Luis Obispo, California. His company performs water audits for commercial, residential and industrial properties throughout central California. “We’ll see sprinkler systems that are so horribly laid out that we won’t even do a catch-can test.”
“The purpose of doing an audit is really to develop an accurate watering schedule,” said Tim Wilson, former education director for the Irrigation Association (IA). Wilson created the current version of the IA’s Certified Landscape Irrigation Auditor (CLIA) training class and manual. He has taught CLIA classes all over the world. As a former irrigation consultant, he’s performed audits on numerous residential and commercial sites.
“What you’re supposed to do is go out maybe two or three weeks before you lay out the catch-cups and evaluate the site. Make a list of all the things that are broken. Give that list to the owner, and have him get everything fixed, so the system is in perfect condition. And then you come out and do the audit,” explained Wilson.
What’s really needed are two audits, he says; one, before everything is fixed, and one after. But clients probably won’t pay for two audits. And, they might balk at the expense of repairs, which, on a large commercial site, could run into the thousands—even the tens of thousands of dollars—if a system hasn’t been maintained well.
“One reason for doing an audit is to do it comparatively,” said Kurt K. Thompson, irrigation director for Orlando, Florida-based Massey Services. “You say, here’s a typical zone of sprinklers, let’s do a catchcup test. That sample sets a benchmark. After you raise, straighten and re-space the heads, and make sure the water pressure is right for that test zone, you do another catchcup test. That gives you a clear before-and-after comparison.” Once you show them that, said Thompson, the site’s owners usually give the go-ahead to do all the necessary repairs on the entire site.
Water’s continued scarcity is making auditing more important than ever. In Albuquerque, New Mexico, audits are required on all new developments over one-half acre. The ordinance requires a 60 percent Distribution Uniformity (DU) for all fixed spray systems and a 70 percent DU for all rotary systems. The language even states that the audit should be performed by a CLIA, in accordance with the IA’s auditing manual.
DU lq stands for ‘distribution uniformity, lower quarters.’ To calculate it, an auditor takes the total volume of the water collected in the lowest 25 percent of the catch-cans, and divides that number by the total volume of the water collected in all the catch-cans. The purpose for this is to focus the watering runtimes for the driest 25 percent of the sample area. The lower the DU number is, the worse the system is performing.
“When you say, ‘irrigation audit,’ it means different things to different people,” said Thompson. As a certified landscape irrigation auditor, a certified irrigation designer and certified landscape irrigation contractor, what it means to him is the IA’s international auditing standard, based on calculating DU.
“You want the highest uniformity possible,” he said. “The more catchcups that are closest to the average value, the more uniformity we have. That means there are fewer dry spots in relation to the rest. A low
DU number means that some of the areas are going to get a lot more water than others, in order to irrigate the driest areas, at the very minimum.”
Here’s how it’s done. An auditor first identifies a test area that looks like it’s going to be representative of the entire site. He then lays out containers, called ‘catch-cans’ or ‘catchcups,’ in a grid pattern, at fixed distances from the irrigation heads.
“For spray sprinklers, they’ve got to be low enough and just a couple of feet away,” said Thompson. “With rotors, larger sprinklers that throw 40 or 50 feet, the catch-cups have to be two to four feet away.”
“We try to ensure that we have no fewer than 24 catch-cups,” said Thompson. “From that, we get two empirical outputs of data. A net precipitation rate—that’s simply how much water is being rained down on the landscape—and a ‘DU lq .”
Thompson explains further. “It’s impossible to achieve 100 percent DU. Seventy percent is about as perfect as we can get. It’s the geometry of what we’re irrigating,” he says. Installers have to follow the contours of the landscape, so that when sprinklers are placed, they don’t get exactly square spacing.
“Clients keep saying, ‘What do you mean you only get 70 percent? You can’t get me 80? 90?’” That’s one reason Thompson’s company no longer expresses DU scores as percentages but as decimals, like 0.7 rather than 70 percent.
Thompson says that “the DU number is not, in itself, useful to me at all, other than for scheduling. Ninety-five percent of the time, we use it as a diagnostic tool. It’s not the silver bullet, it’s just one of a zillion things we do to analyze the actual potential for water waste.”
What Thompson finds even more helpful as a diagnostic tool is to put the volume of each catch-cup on a diagram of the sample area, with dots for where each sprinkler is located. That gives him a clear, graphic representation of what’s going on.
Do irrigation audits save?
So, do irrigation audits conserve water or not? The answer seems to be, ‘Usually.’ “Here’s the real deal,” said Thompson. “What we’re trying to do with water management is not so much conserve water, but conserve wasted water. We want to make sure that the water we do use is effective, not leaching out fertilizer, not running off into the street.”
Auditing is supposed to be a water conservation tool. But is it? Wilson isn’t so sure. In 2009, he wrote a paper in which he stated his concern that, at times, calculating DU lq can actually increase water usage, because the numbers are based on keeping everything green. “People lay out these catch-cans and calculate a uniformity number. That uniformity number will then inflate the watering time that you would normally run the station, so that you don’t have any dry spots. What happens quite often with these schedules is that they end up with watering times that are longer than a person would normally have if they’d never done an audit.” DU numbers also don’t take into account soil/moisture movement from wet areas into drier ones, he says.
Thompson concedes that after an audit, water usage could conceivably increase, “if the system wasn’t watering well enough to make healthy plants to begin with.” Sometimes, a sprinkler system hasn’t been used much due to its poor condition, so a groundskeeper simply turned it off. Obviously, any schedule you subsequently set up in that circumstance will increase water usage.
Wesolowski cites an example where auditing did save a client water, lots of it. “We had a three-year-long contract with the city of Arroyo Grande, California. We audited all their parks. In one case, we saved them 60 percent on water in one year, and that’s because we did an audit. We were able to accurately see what the (water) outputs were.”
In this case, Wesolowski discovered that the irrigation system in one particular park had low water pressure, but was fitted out with spray heads that required high pressure. “In an attempt to gain coverage with the system, the groundskeepers kept putting larger and larger nozzles on, with less and less pressure. They were putting out columns of water that weren’t effectively doing anything.”
“After doing the audit, we were able to recommend a complete head change-out to a different product that operated at a lower pressure,” continued Wesolowski. “With the lower-pressure heads and smaller nozzles, we were able to increase the head pressures and get the distance for the coverage. On certain sites, there is a definite benefit to auditing.”
Reducing water usage
Post-audit, there are other methods to help your clients reduce their water usage. Thompson installs smart controllers wherever possible. One incentive for doing so is that his state, Florida, has mandated only two days of watering per week during the summer, “but if you have a smart controller, you can get variances to let you water up to six days a week.”
However, Thompson cautions, installing a smart controller isn’t the elusive single solution that fixes everything. “Putting a smart controller on a poorly designed irrigation system is the epitome of putting lipstick on a pig. Unfortunately, we see this all the time. People will say, ‘Well, we’ll hang this good controller on the wall,’ but the rest of the system still stinks.”
Thompson adds that reducing a client’s water bill involves a number of techniques. Among them: maintaining separate zones for turf and shrubs; not mixing spray heads and rotors; using the manufacturer-specified water pressure; and installing smart controllers and rain sensors. “My slogan has always been, ‘Water when needed, not when scheduled.’”
Once a landscape is built, however, the plants, soil and irrigation system can’t be managed separately, according to Thompson. “They have to be comprehensively managed. It really has to start in the dirt, with decent soil. You have to have the kind of soil that can support the right water/ oxygen and biology mix, in addition to the nutrients that are in there. And then you have to plant the right plants, those suitable to the sun exposure and the climate. When you have that, plants aren’t sitting in a state of stress all the time, and their need for water is not as acute. Plants that aren’t under stress tend to be more forgiving and self-sustaining.”
Thompson said, “We get customers asking us to ‘fix the sprinklers all the time,’ when they’re not the problem.” He cites the example of a customer who couldn’t get grass on a certain median strip to grow, and blamed the sprinklers for not watering enough. “The lawn in this 30-foot-wide strip had 14-inch caliper oak trees. You could flood it every day, and it wouldn’t make any difference. The trees are going to suck every bit of moisture out before the turf can get any.”
A good skill to acquire
Adding “Certified Landscape Irrigation Auditor” to your list of qualifications gives you the opportunity to add another service to your menu. To become a CLIA under the IA’s program, a landscape contractor must have at least one year of professional experience, pass a written exam, and submit a completed water audit that must include one rotor and one spray area for evaluation, verified by an IA-certified professional in good standing. “It shows that you have the expertise needed and that you’re better qualified to evaluate irrigation systems,” said the IA’s industry development director Brent Mecham.
The good news for property owners is that many water utilities offer irrigation audits free of charge for their customers, even for large commercial developments. That’s not necessarily bad news for contractors, says Wesolowski, who is often hired by municipalities to do their audits.
“The nice thing about it is, they (the utilities) don’t go overboard and start fixing things. They’ll give the owner a list of contractors who can get their systems up to speed. When we go to sites where they’ve had city audits, they’ll say, ‘We’ve got too high a pressure; we’ve got this, we’ve got that.’ In effect, it helps us, because the city has already troubleshot the major issues. Then we just address them.”
If you become a CLIA, you probably won’t be able to give up your day job. Wilson says that only a small percentage of CLIAs earn their living from audits alone. It’s still a worthwhile skill to acquire, and a good program to go through. “The CLIA program is a great educational tool,” he said. “When students walk out of that class, they understand soil/plant/water relationships like they never have before. And it makes them better irrigators. That’s a real, substantial benefit.”
Learning to become an irrigation auditor can only help you improve your skills and be better at your profession. Even if it doesn’t expand your bottom line that much, remember that education is never wasted.
However, water often is.