DIY Irrigation System Design-Getting Started


You'll need a pressure gauge (see your Rain Bird dealer), string and a pencil or pen, a 5 gallon bucket and a tape measure.





What Is Your Water Pressure?

Screw a pressure gauge onto an unregulated outside faucet. Make sure no water is running anywhere inside or outside your house. Turn on the faucet with the gauge attached. The gauge shows your water pressure bar. (Record your results)

• Open the tap fully, with the gate valve in the rig closed.
• Note the pressure reading at no flow
• Open the gate valve slowly and start measuring the water flow at the highest pressure available e.g. Open valve slowly until the gauge reaches 4 bar. Then direct the rig hose into a bucket and time how long it takes to fill 20 litres. Write this result down
• Do the same for 3.5bar, 3 bar and 2.5 bar
• You will notice the lower the pressure the more flow, your flow and pressure readings should look similar to the figures below:
 
Pressure Reading at Gauge Time to fill 20 litre bucket Flow in litres per minute
(20l divided by seconds x 60 )
4 bar        40 seconds     30
3.5 bar     35 seconds     34
3 bar        30 seconds     40
2.5 bar     25 seconds     48


What Is Your Water Meter Size?

The meter size ( 5/8",3/4" or 1") is usually stamped on the outside of the meter. If you can’t find the size, just call the water utility company and ask for that information.

Record: Write the meter size (5/8",3/4" or 1") on your worksheet.

Using a borehole/Pump?

Check with your pump owner’s manual to determine its pressure and flow capacity. If you're unsure, ask us to assist you.



How Large Is Your Service Line? 

Find the pipe that runs from the water meter to your house. Wrap a piece of string around the pipe, mark it, then measure how much string it took to go around the pipe. Check your string length on the table below to find your service line size.

Record: 3/4", 1" or 1 1/4" on your worksheet

For example, if your string measures 4" and you have galvanized pipe, your service line is 1 inch.

Determining Size of Service Line: (1''=25mm)

Length of String2 3/4"3 1/4"3 1/2"4''4 3/8" 5"
Size of Copper
3/4"    1"    1 1/4"    
Size of Galvanized
   3/4"    1"    1 1/4"
Size of Sch. 40 PVC   3/4"   1"   1 1/4"


What Is Your Home's Water Flow?

Get a measurable container, like a 5 liter bucket, make sure no other water is running in or outside the house, turn the faucet on all the way and time how long it takes to fill the container.
Record: Liters per minute (LPM) on your worksheet.

Determine liters per minute (LPM) with the following formula:

Important: retest if less than 3 LPM. Are the two test results different? 
Call us if your have any questions.

These readings are very important as different sprinkler require different pressure to work correctly and with this information we will be able to design the system correctly.

Sketch Your Yard (If you would like us to assist you)

Tip: Use scratch paper first then transfer your final drawing to the enclosed graph paper. Use bold, black lines only, no shading.

Divide your lot into sections such as front lawn, side lawn, flower beds, slopes, etc., and label all those areas you want watered. Also be sure to include the house, driveway and sidewalks in proper scale. If you have special watering preference such as bubblers in planting beds or a drip irrigation zone, note that on your drawing as well. Group similar types of plants such as shrubs and ground covers together in the sections. If you have big differences in the amount of sun different areas get, you may want to group those for watering efficiency and indicate “separate valve” on your drawing.

Other items which will also need to be shown:

•The position of the tap where the test was performed must be clearly marked
•The preferred position of irrigation controller( if a automated system) must be shown
•Any services running through the property ( this is to protect the irrigation contractor as to not dig in areas where there may be electrical, telecommunication or other water pipes)
•If there are any boreholes or alternative water sources on site please forward all information with the drawing e.g. Position of borehole depth flow etc.
•An example of a drawing we require is shown below:

This is also a very important part of the design process. With incorrect or incomplete dimensions given to us the design may not allow for all the areas to be irrigated correctly. The following steps must be followed in order to help us do a professional design for you.

Once we have all of this information we will be able to produce an irrigation drawing (using design software such as AutoCad), bill of quantities and a list of contractors in your area. These projects normally take a few days to finalize, but our design team will let you know on time frames.



E-Mail or fax the completed drawing to:

Sheldon@conirr.co.za
Fax: TBC

Controlled Irrigation offers this design service as a guideline. No guarantee of accuracy of design, system installation, or operation of system is implied.