Efficient watering practices

Efficient Irrigation for water conservation guideline was introduced in March 2009 under the Queensland Plumbing and Wastewater Code and applies across Queensland for all new installations of irrigation systems. If you are planning to install a new irrigation system for your garden then you will need to be aware of, and comply with this guideline.

This guideline applies to the use of all irrigation systems including existing irrigation systems connected to a town water supply within the Toowoomba Regional Council boundaries.

The document - Efficient Irrigation for Water Conservation Guideline - linked to this article was developed by Qld Water Commission and applies to all areas within Queensland and the use of irrigation systems are subject to council's' water restrictions. 

Watering tips for gardens

Planning your garden
When planning a new irrigation system or modifying an existing system you should select the system and emitters which are efficient and appropriate for your:

  • soil type of your garden
  • plant selection
  • microclimate

For example, drippers are an excellent and water-wise irrigation option for most gardens, but may not be suitable for sandy soils.

You should consult your local irrigation professionals, horticultural specialist or nursery to determine which system(s) are right for your garden. Your irrigation specialist may design a different type of system for different parts of your garden. Your emitters should be planned and placed appropriately in order to water effectively. Take a simple plan of your garden along to your local retailer or irrigation specialist so that they can help you design a system which will distribute the right amount of water in the right places.

Understanding how much water your garden and lawn requires
It’s easy to over water gardens and lawns if we don’t understand how little water the garden or lawn actually requires. Just because you can water for a certain period each week, doesn’t mean your garden or lawn actually requires this volume of water. Depending on the type of efficient irrigation system or efficient sprinkler you have, you may only need to run it for a very short-time before the required amount of water is delivered to your garden or lawn. You can find out how much water your garden and lawn requires by:

  • doing the water meter test to determine the output rate of your emitters (litres/minute); and
  • finding out the precipitation rate of your irrigation system

Water meter test - helps determine the output rate of your emitters (or they may be calibrated).

Precipitation rate - means the volume of water (in litres) applied by the efficient irrigation system to a defined area (square metres) over a specified period of time (minutes).

As a guide:

  • well-designed gardens may only require around 10 mm of water each week to sustain growth
  • water smart lawns will require even less water – as little as 6 mm in summer when they are growing and 3mm in winter when they are dormant. This volume of water includes any rainfall your garden may have received.
  • Ensure soil is dry enough to warrant watering (so no need to water after rainfall).
  • Calculate garden water needs. The volume of water required for your garden or lawn will depend upon your soil and plant type(s) (see below).

You may work out the amount required yourself by using a simple example as a guide or seek professional advice from your local irrigation professional, horticultural specialist or nursery.

Take note of the rainfall your garden and lawn receives
If your local area has recently received significant rainfall (more than 50 mm) it may be weeks before you need to water again.

You must have a soil moisture sensor or rainfall sensor connected to your efficient irrigation system. This will prevent the system operating if the soil already has adequate moisture or if it is raining. There are two ways in which you can determine the volume of rainfall your garden receives each week:

Install a rainwater gauge
Check the rainfall figures from the nearest Bureau of Meteorology (BOM) weather station closest to you house on the Bureau of Meteorology site - BOM.

Apply water correctly
To ensure your garden and lawn is receiving the maximum volume of water from your irrigation system or sprinkler and water is not being wasted, you should ensure your emitters are:

  • applying water only to the root zone of the plant, where the plant can actually use it
  • spaced to ensure adequate and even distribution of water or as otherwise recommend by the manufacturer
  • adjusted so that you are not watering buildings or other hard surfaces such as paving
  • Don’t allow water to pond, pool or run off
  • Don’t water in windy conditions
  • Mulch gardens to reduce evaporation

Seek advice from your irrigation professional and/or your horticultural specialist or nursery when designing or installing a system.

Make sure you only water during the permitted times under the current level of restriction applicable in your local area. If in doubt check with Council. It’s important that we monitor and manage our water use to ensure excessive amounts of water aren’t used. In general, Target 200 can be achieved by restricting household outdoor water use to around 1.5 hours per week in total.

Remember, for the health of your garden and lawn, you should only water for the time it takes to meet the water use needs of your garden or lawn.

Alternative water sources
More than a third of households in SEQ now have a rainwater tank and many households have been using rainwater for some time to sustain their garden. Always use rainwater before using your town water to irrigate.

Some households also use greywater on their garden and lawns. This can save thousands of litres of town water each year, but there are requirements associated with the use of greywater around the home. For example household greywater must not be sprayed or used in your irrigation system or sprinkler.

Some useful weblinks

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