Using an unlicensed irrigator to install your sprinkler system may seem to save you some money upfront, but in the long run it’s going to cost you more for repairs and to re-do the installation properly.
Not only is it risky to hire an unlicensed irrigator, but the law in Texas stipulates that “a person may not sell, design, install, maintain, alter, repair, service or inspect an irrigation system — or consult in these activities — in this state, unless the person is licensed by the TCEQ.”
Chances are that unless you hired a trained, licensed irrigator, there are some hidden disasters waiting to happen in your sprinkler system.
The Importance of design
A successful irrigation system starts with a proper design. And it’s much more than deciding where to put sprinkler heads. Some of the basics include:
- Checking local codes and permit requirements.
- Locating site utilities.
- Determining soil type.
- Obtaining or drawing a site plan to scale and comparing it to the site.
- Determining water pressure (psi) and gallons per minute (GPM) available from the water connection.
- Calculating pressure losses from chosen sprinkler equipment (e.g. water meter, backflow preventer, sprinkler heads, etc.).
- Making pressure loss adjustments to balance the system.
- Determining the correct distance between sprinklers, their precipitation rate, and the GPM for each head.
- Marking the sprinkler heads on the plan.
- Identifying hyro-zones for various plants and creating valve zones.
- Drawing in the pipe layout.
- Calculating lateral piping sizes.
A poorly designed plan by unlicensed irrigators, or no plan at all, creates many problems. Here are some issues that licensed irrigators run across, and have to diagnose and repair:
- Incorrect head layouts
Too many sprinkler heads on one zone lowers the water pressure for each head. The heads will barely shoot water, and the lower pressure can also prevent pop-up sprinklers from popping up. Too few sprinkler heads leads to inadequate coverage of plant material. Some areas will be under-watered, becoming dry and brown, while others near the sprinkler will be over-watered, as the homeowner tries to compensate by irrigating more often. The spray from each sprinkler should be reaching all the way to the next sprinkler in each direction for 100 percent overlap, in what is known as head-to-head coverage.
Runoff occurs when sprinkler heads are installed too close to structures, sidewalks, and driveways.
- Mixed heads with different pressure ratings and precipitation rates in the same zone
You should only use sprinklers with matched precipitation rates and pressure ratings in the same zone. Stick with one brand and model of sprinkler for the zone because precipitation rates differ between makes and models — if you mix a high precipitation sprinkler with a low one in the same valve zone, one area will be over-watered, and one will be under-watered. It’s fine to use a different type of sprinkler in a separate zone (e.g. brand “x” spray heads for a small lawn area on one valve, brand “y” emitters for the garden on another valve, and brand “z” for rotors for a larger lawn area on a third valve).
Also, in order to achieve matched precipitation rates in a watering zone, a professional knows how to choose the correct GPM nozzles for rotor sprinklers in order to proportionally match their precipitation/application rates. A rotor that’s watering a 1/2 circle should have a nozzle installed that is applying 1/2 of the GPM that the nozzle in a full circle rotor sprinkler in the same zone is applying.
Nozzles for spray sprinklers also need to be matched for precipitation rates and distance in the same zone. You can’t just take a different brand nozzle and screw it on a sprinkler body if the performance specifications aren’t the same, and expect it to work properly.
- Improper installation of drip tubing and emitters
A trained, licensed installer has to match the proper emitters with the needs of the plants and the soil type. If the emitters are placed too far apart, are too few in number, or don’t meet watering needs, the plant roots may not develop properly.
Types of emitters include: soaker hose, pre-installed emitter lines, punch-in emitters, micro sprays, and micro bubblers. Soaker hoses, emitter hoses, and micro sprays are better suited for closely spaced plants, while drip emitters are better for areas with wider spaces between plants, or for separate plant containers. Micro sprays are not as efficient as ground drip emitters, as they can lose water due to evaporation.
Micro bubblers are best for larger plants, such as shrubs or roses, and for filling the basins around newly planted trees. The micro sprays and bubblers should be placed on a different zone from the emitters due to their higher flow rates.
In-line drip tubing (with pre-installed emitters) should be laid at 18- or 24-inch intervals. Unlicensed irrigators have installed the tubing incorrectly by running it in areas where there were no plants, running the lines too close together, not placing the tubing close enough to the plants, and creating tangled, overlapping piles of tubing.
User-installed, or punch-in emitters, provide more versatility than in-line tubing, and allow customization for a variety of plant sizes and irregular plant spacing. These can be installed on in-line tubing as well. A licensed irrigator has to know the output rates for various emitters, which range from 1/2 to 4 gallons per hour (GPH), so he can compensate for plants close together with differing water needs.
Unlicensed irrigators also cut costs by using emitters that clog easily and distribute water unevenly, rather than installing the better quality turbulent-flow, diaphragm, adjustable, or pressure compensating emitters.
Troubleshooting the irrigation electrical system can take many hours. Often the problem comes down to shoddy workmanship, and the use of improper materials by unlicensed irrigators. For example, regular splice caps being used rather than special waterproof splice connectors. Any water leaking into the splice will corrode the wire and short it out, or create an electrical open. Sometimes wires are stripped too far back, or twisted too loose or too tight, and fail after only one or two years. You’ll also find many inappropriate types of wire not approved for direct burial, such as communications cables, speaker wire, thermostat wire, telephone wire, and lamp cord.
In temperate zones, the typical pipe used for lateral pipes is 1-inch CL (Class) 200 PVC (polyvinyl chloride). It performs well under frequent use and higher water pressures. The recommended sealer for threaded fittings is PTFE (polytetrafluoroethylene) thread seal tape, often called Teflon tape. This tape needs to be wrapped correctly with the right thickness to create a strong, leak-proof pipe.
For slip connections, PVC primer and cement are used (“solvent welding”). Unlicensed irrigators often take shortcuts by using only the primer or cement. Sometimes they also just glue the fitting and not the pipe, or vice versa — the result being future leaks needing repair. They also cut corners by not burying all the barbs inside the pipe if they cut it short, leaving some of the barbs sticking out. The fitting then won’t set properly, and will come loose at some point, especially under high pressure.
Lateral pipes should be buried or trenched at least 10 inches deep to protect them from cars driving over them, shovels, and lawn aerators. Unlicensed irrigators bury the pipes too shallow, often 6 inches or less, making them highly susceptible to damage. As well, they often use a cheaper, smaller pipe with a very low flow capacity that plugs up easily. If they also use too much glue on the fittings, they can partially block the flow of water, severely affecting the sprinklers.
Incorrect controller programming
Irrigation controllers have to be programmed correctly to nourish lawns and gardens, and to conserve water and save you money. Unlicensed irrigators improperly program controllers in the following ways:
- Not caring about or aware of your specific watering days and allowed watering times.
- Not knowledgeable about the watering needs of your plant materials (overwatering and/or underwatering).
- Not aware of the cycle and soak irrigation method.
- Not installing a rain sensor or shutoff device for new systems or when replacing a controller (a TCEQ requirement).
- Programming all programs (e.g. A, B, C) so they all run, even though you don’t need them (overwatering).
- Confusing start times with zone run times, and programming start times in all the zones (overwatering).
- Not knowing how to use the “seasonal adjust” feature.
Sprinkler design, installation, and maintenance is a skilled activity. Be sure to hire a licensed irrigator.
For prompt and skilled service to your sprinkler system, call the pros at South Austin Irrigation at (512) 534-7449.