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Understanding a drip irrigation watering system

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Understanding a drip irrigation watering system

Drip line and poly pipe.Drip line and poly pipe.Traditional watering systems use sprinkler nozzles to distribute water above ground to plants. This can be unreliable as water may be lost to wind and is more vulnerable to loss through evaporation. The effectiveness of a system can also be dramatically reduced by something as simple as foliage being in front of a spray head.


A drip irrigation system uses irrigation pipe that has pressure-regulated drippers embedded in the line at set intervals. These drippers deliver a set number of litres per hour even at lower water pressure. Drip line is usually installed under mulch. It is an accurate way to deliver water exactly where it’s needed and, as it is delivered slowly, penetration into the soil is more reliable and consistent with little or no run-off.


For a small system, all piping and connecters will be 13mm. For a larger system the supply and connection lines may be 19mm, while the drip line will still be 13mm with step-down joiners used to connect. The exact design of a system will vary with your garden’s needs.


Low volume layout.Low volume layout.   High volume layout.High volume layout.


Delivering water only to the base of plants is ideal for a garden with low water demands. This may be in an area with reliable rainfall or heavy soil that retains moisture well. It may involve using a plain poly-pipe return line to finalise the pressure loop.


A higher volume layout delivers water across the planted area. This sort of design is used with plants that have higher water needs or in gardens with more open or sandy soil.

You will notice with both designs that the system does not have any dead ends. They are both loops. The reason for this is to avoid sections of lower pressure in your system. With a loop, the pressure will equalise in the lines and the output will be equal through all drippers.


For a step-by-step guide, see How to install a drip irrigation watering system.


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New Contributor

Re: Understanding a drip irrigation watering system

Thanks @Adam_W , this is quite helpful.


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