Irrigation Dos and Don'ts

Industry experts say paying attention to irrigation design and details, and not taking shortcuts, makes all the difference in the world of water, as it does in other aspects of business. Currently, the details are even more important than they were in the past. Water is becoming scarcer and more expensive in many parts of the United States.

What to Watch Out For
Hammering. A common mistake some irrigation contractors make is that they overestimate the gallons of water needed, a miscalculation that results in hammering, or a banging sound in the irrigation pipe when the water is flowing. More than just a nuisance, that sound can be wreaking havoc on the entire irrigation system.

Fixing the problem can cost a homeowner two to three times what was paid for the original system, says Jess Stryker, an irrigation consultant with Ventura, Calif.-based Jess Stryker and Associates. "With a little pressure you can shove a lot of water through a very small pipe," he says. "But just because you can do it doesn't mean it's smart."

Any irrigation system you install should come with a detailed list of specifications—stick to them.

Back Flow. Back flow results when water from the irrigation system backs into the home's plumbing system—the water homeowners use for sinks and bath. To avoid back flow, it is important to install a backflow device, which can cost from $100 to $400, according to Brian Vinchesi, design engineer with Pepperell, Mass.-based Irrigation Consulting Inc. In certain areas, such a device is required by local regulations. Check your municipality's building codes before installing an irrigation system to be sure you're in compliance.

Over-watering. More the fault of the homeowner, not the landscaper, over-watering can ruin carefully planted lawns, tress and shrubs. Vinchesi says that many homeowners tend to over-water because they don't know how to work the system's water scheduling function or because they don't know how much water is needed.

"Homeowners spend $2,000 to $5,000 for an irrigation system," Vinchesi says. "But then they set the water and forget about it."

Obviously, the first way to remedy the problem is through communication. Be sure homeowners understand how to operate the system and give them detailed watering instructions. Vinchesi says another possible solution is to consider installing a weather-based irrigation system, which does its own scheduling.

If you do chose a weather-based system, which detects conditions like rain and humidity, make sure to chose the right sensor and placement, says Rob Tilson, president of Vienna, Va.-based Tilson Group, a landscape architecture and construction management firm.

"Sensors placed on a roof tend to be more accurate," he says. "Sensors placed on the ground of a property with an undulating landscape, for instance, can give inaccurate readings."

Planting. Another very basic but common mistake contractors make is installing the irrigation system before all trees and shrubs are planted. Dennis McKernan, an education director for the Falls Church, Va.-based Irrigation Association. "The planting and installation of piping have to be coordinated so you don't damage the piping," he says.

Hire a Pro
If you don't fully understand all the plumbing aspects of irrigation, such as water pressure, hire a certified irrigation designer, experts say. It's not worth the hassle and the cost of replacing a faulty system should something go wrong.

The Irrigation Association offers information about industry certification, which is different from licensing. Certification is a professional credential that states a contractor has completed a course of study, passed an exam and met specified criteria. Certification typically is issued by private organizations. It sets standards and ensures practitioners are educated and competent.

On the other hand, licensing is required by a state or local government and gives permission to ply a trade. If contractors violate the licensing law—either by acting without a license or failing to uphold the rules governing the license privilege—they could be prosecuted. According to the Irrigation Association, only a handful of states require licensing: Connecticut, Louisiana, New Jersey, Rhode Island, South Dakota and Texas.

In some cases, the Irrigation Association can provide on-site certification, as long as there are at least 15 people in each class. Various companies can sponsor a class. During 2004 the Association conducted more than 100 classes in 50 different locations in the United States and Canada.