What parts do I need to install a complete irrigation system?
No matter where you are, systems break down to common components. Details do vary by climate and code but the basics remain. The sizes and quantities of each depend on the system. I’ll list the basics first and some of the exceptions at the end.
Starting at the end and working back, you will need something to spray the water, usually popup sprayers with nozzles, shrub sticks with nozzle adapters and nozzles, or rotors.
To connect these to the underground pipe you need either a cut off nipple or a swing joint. Swing joints are the most versatile and can help prevent damage over time. Risers will connect directly to the pipe with a Tee.
You will need PVC pipe and fittings. The main runs need to be Schedule 40. The laterals, or zone lines, can usually be Class 200. Local codes may have restrictions so check first. Fittings are the straight connectors, elbows (90 and 45 degree), reducers, couplers, Tee’s for risers and generally anything that connects the PVC to PVC, including connecting to valves.
Speaking of valves, you will need some. Each valve controls an individual zone. They turn the water on and off for that area. They go in valve boxes.
Before the valves in the water line you have a backflow preventer. This keeps contaminates out of the drinking water. Be sure to check your local codes for requirements. EVEN IF YOUR AREA DOES NOT REQUIRE A BACKFLOW, put one in. It’s for your protection. Insulation for the backflow in most areas of the country. Also pipe insulation.
Finally, above the backflow in the water line you have two optional parts. An isolation valve, usually a ball valve, to turn water off to the system in case of breaks and leaks. It’s not required but someday you will want one. Put it in. You may want a master valve. This is a standard valve used in a special manner. Speak with your designer about these.
You notice I have not mentioned copper pipe and solder. If your code requires you use this, and you are not very experienced in their use, get a professional. It can be difficult and painful.
Last in the line is the brain. Something has to tell the system when to come on and what to do. This is the controller. There are many types and models with varying features. If there is any chance your landscaping will change over the next few years, get one that is expandable. Modular is best.
You will need lots of wire, usually in red for power, and white for common. Multistrand is also available. Wire connects the controller to the valves. It’s the nerve path from the brain.
Tools and Why You Need Them:
For the Soil
No matter how much you hate it, you are going to need a trench/ditch. While any shovel will dig a ditch, some are better than others. First, if you can use a trenching machine, do so. Life is short. Digging is long. HAVE SOMEONE LOCATE ALL UNDERGROUND UTILITIES BEFORE YOU DIG. Call 811. Don’t say I didn’t warn you.
If you must dig by hand, get a sharpshooter. You don’t need a wide trench and will waste time and energy using a standard shovel.
One shovel you may not have heard of but is valuable for cleaning out the bottom of the trench is a CLEAN OUT SHOVEL. You want the bottom of the trench to be relatively smooth and free of debris/rocks. These can cause pressure points on the pipe, leading to cracks and breaks.
For smaller PVC pipe or flex/funny pipe you can use a hand trencher. Instead of digging a ditch this makes a narrow “V” shape in the soil. Good for short runs.
Sometimes you need a pick or pickaxe to break up hard, dry soil. If this is so, consider the trenching machine.
For the Pipe
You need to cut the PVC. You can use a hacksaw, pipe shears, ratcheting shears, hand saw or a cable saw. You only need the cable saw if things have gone very badly and you must cut a pipe out of the trench. For larger pipe and neater cuts, use the hacksaw. The shears are for 1” and below and best for the lighter, thin wall pipe. Have some sawhorses or blocks to hold the pipe off the ground while you cut it. You’ll do enough kneeling later.
Cement and primer to glue the pipe together. Leather gloves. You’ll be surprised how sharp PVC edges can be. A rough file can be good for smoothing edges of pipe cuts.
Pliers, particularly along the line of pump pliers. They are great for when the pipe gets wet and slippery. Pipe tape for the threaded PVC to brass or PVC connections. Rags. More than one.
For the controller and wiring.
Wire strippers for cutting and stripping wire. You will need waterproof connectors for the underground connections, standard wire nuts for protected connections. Whatever screws are needed to mount the controller. Have a slotted and Phillips screwdriver handy.
Cold weather areas have their own challenges. The backflow may be removed in the winter, so you would add union couplings and eliminate the insulation. If the ground freezes to any depth you would install freeze drains and/or use poly pipe/flex pipe instead of PVC. PVC becomes too brittle below a certain temperature. You may put in an adapter to let you hook an air compressor to the pipe to blow out the system before a freeze.
Drip irrigation is usually installed on only one or two zones in a system. Requirements include a valve, pressure reducer, and filter. Common assemblies are here. You also need drip line, connectors and emitters. A good example of the general assembly is here. If you are installing a drip system you might need a crimp tool and punch.
A Final Note:
Local codes always determine what material you may use. Make sure you check them before you spend anything.