Sprinkler supplies and garden items

Planning your Lawn Irrigation System



Pre-installation steps for Lawn Belt

Before we start your irrigation system design we’ll need to take a couple of readings from your garden spigot.

1. Water Pressure (PSI)

Optimum performance of your Lawn Belt irrigation system is based on 40-60 psi (pounds per square inch). If you are operating a water pressure between 30-40 psi special adjustments can be made (see #3 below).

Buy a pressure gauge (only 8-$10 at your hardware store) This will give you the best reading at your spigot.

If you can’t get a gauge, call your local water company and ask for the Psi at your meter.

attach a psi guage at the spigot
Pressure gauge at the spigot

If attaching a gauge make sure all water sources both inside and outside the house are turned off. Then simply attach the gauge to the spigot and open the faucet fully. For a more accurate reading test two or three times during the time you’ll be watering, then figure the average reading.

2. Check Your Water flow (GPM)

Suggested GPM for your Lawn Belt irrigation system is 8 GPM (gallons per minute). Here’s a quick method to checking. Get a gallon bucket and fill it at the spigot. Time how many seconds it takes to completely fill the bucket. Then apply the following formula:

GMP Formula Calculation
60 / Seconds to fill 1 gallon

Example: If it takes 7 seconds to fill a gallon bucket then divided 60 by 7 .. or 8.6 GPM

Note: Some newer spigots have a higher restriction on the flow – meaning that your Gpm reading may be slightly lower than actual.

3. Find the coverage of irrigation system

Proper sprinkler placement is another key to an effective irrigation system. Focus on placing all the heads in your design first is a critical step.

On average each sprinkler head in our standard sprinkler kit will spray 15 – 20 feet in diameter. If customizing your system refer to tables in out store (click on custom sprinkler kit) If you have good pressure (above 60 psi) your spray may exceed 20 feet. If your water pressure reading is a under 40 psi you may consider either decreasing the diameter of your sprinkler by adjusting the screw on top of the head or as a last resort try removing one head from your zone.

adjusting the diameter spray of your sprinkler head
Adjusting the diameter of spray
(may differ as shown depending on head you select)

4. Plot your sprinkler heads

The critical step in your sprinkler system design is to decide which areas you want to water, and what kind of spray patterns you’ll need. Use the grid sheet (below) and plot the outline of your garden area. Include any obstructions such as driveways and patios. Use a tape measure for accuracy, and make sure all the areas match the scale of the grid. (Our grid scale below is 1 square = 2 feet)

5. Draw a garden plan

Properly positioning your sprinkler locations is an important step. As you design the layout, try to maximize the amount of Lawn Belt you have while keeping track of remaining Belt left as you establish each sprinkler location.

Start by drawing a line from the spigot to your first sprinkler head (radius circle) find the radius size with the chart above. Where sharp corners occur consider using a 90 degree sprayer if possible. Use the spray pattern template below for best results.

Print plot plan and spay template for easy layout

print a grid to layout your sprinkler system
click on image
garden.pdf
print a spray template to layout your sprinkler system
click on image
sprays.pdf
<—- Here’s a printable grid sheet and spray pattern template to easily plot your sprinkler system design. Acrobat reader is required (its free) Click on each image to view and print on 8 1/2″ × 11″ paper.

print a spray template to layout your sprinkler system
click to download free viewer
if images dont open

And remember…

Avoid any tight turns in your layout – use large sweeping turns instead. As you draw each circle and head location try to achieve the most uniform coverage. You can accomplish this by overlapping each circle into the next by about 30-40% (this will create an over spray so you won’t get any dry spots in your lawn or garden when pressure varies).

Details on how to Install Irrigation System