Sprinklers System Zone Layout

1. 3/4" PVC pipe Schedule 40
2. 3/4" Slip PVC Tee
3. 3/4" Slip x 1/2" Thread PVC Elbow
4. Barbed swing pipe Fitting for Swing Joint Attachment

Sprinkler Zone Layout Example

1. Laterals for Separate Zones
2. 1" PVC Pipe Schedule 40
3. 1" Slip Tee
4. 3/4" PVC Pipe Schedule 40
5. 1" x 3/4" Slip Reducer Bushing

Sprinkler Zone Layout Explained

In this sprinkler zone layout example the pipe size remains 1 inch until the second Tee. After this Tee, the piping and fittings remain 3/4 inch up to the Funny Pipe connections. It is a good practice for the pipe size to remain 1 inch (if the available water is 9-16 GPM) until the first Tee, or until the zone has supplied 1/3 of the sprinkler heads. In this example we will assume that the sprinkler heads are 1804's with Rain Bird 15 nozzles. In that case this zone would be using 13.86 GPM, this rate of flow is too high for a 3/4" line to supply. Your objective is not to exceed 5 feet per second. It would be ideal to calculate the flow at each point in a system, but that is not realistic in most cases. Instead, I reduce the pipe size after I have installed 1 Tee that diverts the water relatively equally, or after I have installed the fittings that supply 1/3 of the sprinkler heads.

1/2" PVC

You may have noticed that I have not included 1/2" PVC. I never install 1/2" PVC, I run 3/4" to the last PVC fitting and at that point I use Funny Pipe. I find that this method saves a ton of time and has no adverse effects on the performance.

1. Residence
2. Main Line
3. Zone 1
4. Zone 2
5. Zone 3
6. Stop and Waste
7. Backflow Preventer
8. Automatic Sprinkler Valves
9. Pop-up Spray Sprinkler Head
10. Rotor Sprinkler Head
11. Drip Connection or Bubbler
12. Wiring for Irrigation Valves
13. Irrigation/Sprinkler Timer

This is an example of what the layout of a front yard sprinkler system may be like. The laterals are color coded to avoid confusion.

Sprinkler head layout is perhaps the most important part of your personal installation. If you don't have a proper layout, you won't have good performance and will likely waste thousands of gallons of water each season.

Head to Head Coverage

Head to head coverage is a term you will often hear when having a conversation about sprinklers. In head to head coverage, every spot in the irrigated / watered area needs to be covered by at least 2 sprinkler heads, and each head should throw water far enough that it reaches or slightly overlaps the adjacent heads. This is done by considering each sprinkler as a geometric shape. Each sprinkler head is rated with an ARC and Radius, this provides you with the shape you will use to determine coverage. The geometric shapes will all be based around a circle, while your layout will be based around a square or triangle pattern. This is where inefficiency comes in to play, because you are trying to fit a round object into a square or triangle pattern.

The shapes in the pictures are representing the space between sprinkler heads

Each sprinkler head used in these examples are full heads to help demonstrate how important layout can be.

As you can see, the triangle pattern (actually called a diamond pattern) is more efficient, but it is less common because it is more difficult to lay out. Most residential sprinkler systems are done using the square pattern.

Layout can actually be quite simple. I generally walk around a property with a measuring tape or wheel and place flags according to available products based on distance. Example, starting with a corner, I measure one side or edge of the area to be irrigated, and determine what type and size of sprinkler head will fit best. I then repeat this for every side / edge of the irrigated property until I get an adequate layout to provide good coverage. I then transfer the layout to paper or my computer to see if I have missed anything obvious. I generally pull the property up on Google Earth or Google Maps and take a screen shot, then I use a simple drawing app to apply my layout. There is software that can aid you in setting up your layout, but it is expensive, and it takes time to learn how to use it.

Measure the property for spacing of Sprinklers

Create a layout using sprinkler heads; use rotors for larger areas if possible.

This is an example of an actual sprinkler system layout.

As you can clearly see, the layout is good, but there are still gaps in overlapping coverage. This is a common problem, but it is unavoidable.

As you can clearly see, the layout is good, but there are still gaps in overlapping coverage. This is a common problem, but it is unavoidable.

Swing joints are a flexible way to install sprinkler heads. The swing pipe length can be anywhere from 3 inches on up. There isn’t really any limit to the distance of the swing pipe as long you don’t exceed the velocity of the pipe, especially for long runs (I often use swing pipe as laterals for supplying individual sprinkler heads.). The maximum recommended flow for swing pipe / Funny pipe is 3 GPM, but you can exceed this rating for short distances. For sprinkler heads that exceed this velocity, I recommend having a swing joint that is no longer than 18 inches.

Pop-up with Swing Joint

1. Pop-up Sprinkler Head
2. 1/2" Marlex coupled with 1/2" Funny Elbow
3. Funny Pipe
4. 3/4" Slip x 1/2" Thread PVC Tee coupled with 1/2" Funny Elbow
5. 3/4" PVC pipe Schedule 40
6. Optional 3/4" Slip x 1/2" Thread PVC Elbow
7. Optional 1/2" Auto Drain (Generally only 1 installed at the lowest point of each zone)

Rotor with Swing Joint

1. Rotor Sprinkler Head
2. 3/4" Marlex coupled with 3/4" Funny Elbow
3. Funny Pipe
4. 3/4" Slip x 1/2" Thread PVC Tee coupled with 3/4" Funny Elbow
5. 3/4" PVC pipe Schedule 40
6. Optional 3/4" Slip x 1/2" Thread PVC Elbow
7. Optional 1/2" Auto Drain (Generally only 1 installed at the lowest point of each zone)