Intro: Tall Irrigation Head
A residential irrigation system normally consists of sprinkler heads that are mounted in plastic containers buried in the soil of a lawn. Pressure from the water source pushes the head up out of the container on a spring loaded post so that it rests just above the grass to do its job watering the lawn. When pressure ceases at the end of the cycle, the spring on the post carrying the head causes the head to move back down into the container to await the next cycle. This arrangement has the advantage that the sprayer head is not seen the majority of the time and comes up only when actually watering the lawn; all other times it is out of the way of vehicles, people, or other activity as well as improving the aesthetics of the yard and gardening.
This design also has a few issues that detract from the above advantage, however, that include considerable difficulty in maintaining the head because it is hidden in the container in the ground, grass and debris gets into the container and interferes with the head functions, and the spray from the head gets blocked by vegetation which limits its ability to provide full watering scope.
This article provides a tall alternative to these problems in areas where there is no grass and the vegetation is less civilized. The edge of a natural area or where there are shrubs and ornamentals around a foundation or structures like a gazebo. This irrigation head is as tall as one desires (within reason) to get above surrounding plants, it puts the mechanics of the head at waist level for maintenance, and the mechanism is not likely to get tangled by grass or debris. This device also has the added benefit of providing a volume of water to act as a manifold for stabilization of the water pressure somewhat due to the 2" by 5 foot column of water. It does not require a supporting post to reduce the vibration affect of the operation of the head, especially the impulse type of device.
Step 1: Design and Materials
To complete this project, you will need;
- 1 - Five foot section of 2" Schedule 40 PVC pipe
- 1 - 2" slip to 1/2" threaded PVC adapter
- 1 - 2" sleeve connector
- 1 - 2" tee adapter
- 1 - 2" slip to 3/4" threaded adapter
- 1 - 3/4" threaded connector to flex pipe
- 1 - 2" slip PVC cap
- PVC cleaner and glue
- Pipe sealer or Teflon tape
- A sprinkler head of any type. (I use a Rain Bird 25PJDA-C)
- Dark Green paint
- A hacksaw
- A post hole digger
- A shovel
The diagram above depicts the materials as assembled as well as a typical installation. The illustration shows the tee adapter buried at 1 foot below grade which will translate to a two foot post above ground, but I set mine at 6 inches down to give me a higher post. You can add a 3/4" riser of any length to the top of the 2" pipe or use a longer section of pipe, but the higher you go above ground, the more vibration you will get, so there is a practical limit on height.
The materials cost is about $30 which includes a ten foot section of 2" PVC. The cleaner and glue will make many of these stations as will the sealer or tape, so I did not include those items in the cost. Expect about $25 to $30.
Step 2: Assembly
Use the above drawing and images as a reference for assembly.
Begin by cutting a five foot section of 2" Schedule 40 PVC into two pieces; one two feet long leaving the other one three feet long. A hacksaw is the best tool to use for this because the schedule 40 is fairly thick and can be difficult to cut. When working with PVC, it is always advisable to smooth the edges of your cuts with sandpaper to prepare it for gluing.
Lay out your parts as shown in the drawing above. Starting with the cap on the bottom of the two foot section, lightly sand the mating surfaces of the inside of the cap and outside of the pipe. Wipe the dust away. Apply PVC cleaner to these sanded surfaces. Use the same process to prepare the remaining PVC connections.
When all surfaces have dried, apply the PVC glue to the mating surfaces of each connection and quickly slide the parts together fully. PVC cement does not give you much time to adjust and hesitation at this point will lead to a trip back to the store for more parts. I find it better to glue the individual small pieces first and then move on to cement the large pieces together.
When the glued pieces are assembled, use sealing compound or Teflon tape on the 3/4" to flex pipe connector and thread it into the adapter in the end of the tee fitting.
Place a small piece of masking tape or a spare threaded connector to seal off the 1/2" threaded hole in the top of the column and paint the assembly from the tee connector up. The bottom is going to be below ground, so don't waste your paint on that. I use Rustoleum spray paint because I think it is the best no matter what you are painting.
The final piece to assemble is the spray head itself in the 1/2" hole in the top. If you use the Rain Bird head, it is a 1/2" threaded hole and be sure to use sealer on the connection. If you choose a different head, you should match the adapter to your choice.
Step 3: Installation
Now comes the easiest step but one that will work off that doughnut you had with coffee this morning while you were out getting the materials for this project.
If you don't have a post hole digger, I would recommend getting one because you need a hole at least 2 1/2 feet deep and if you dig that with a shovel, the loose dirt will not hold up the new sprinkler head very well. A post hole is only about 6 inches or so across and you can pack the dirt back in around the 2" PVC very tightly and it will become pretty solid. If you must dig a larger hole, I would recommend that you invest in a bag of Quickcrete.
The connection to your water supply will vary with application, so I can't very well guide you there, but I recommend using flex pipe because it will move with any adjustments you have to make and with small vibrations of the sprinkler head.
Well, that's it!....Enjoy your new freedom from standing on your head trying to maintain in ground heads and clearing brush and debris from your irrigation system. I have found myself searching for ways to replace the few remaining in ground heads that I have.