Is it feasible for me to use Greywater?

1. Is my ‘green’ garden area enough to make a system worthwhile?
  • Allow for a minimum area of 12sqm per person in Perth if using a ‘whole of house’ system (baths, showers, laundry)Allow for a minimum area of 12sqm per person
  • A laundry-only system is also feasible – allow a min. 5sqm per person
  • “Garden areas” means trees, shrubs, garden beds and small lawns but not paving or the verge
2. Is the cost within my budget?
  • A laundry-only system is going to cost around $900-$1200 installed, plus irrigation - around $1500 in total
  • A whole-of-house system will typically cost $3500-4500 plus irrigation. As this will be a larger area, total cost will be around $5000
  • Greywater-ready sewerage plumbing is normally installed by the builder and will be on top of these costs
3. Do I have enough time to plan and implement a system?
  • Unless the house is old or on stumps, it's generally easier and cheaper to install a greywater system in a new home
  • Both whole-of-house and laundry-only greywater systems need to be included at the design stage, well before the floor slab is laid, as the separate pipework must be pre-laid
  • If you're not sure of your budget, why not make the plumbing greywater-ready and then install a pump etc. at a later stage
  • Once the build is underway it's too late to easily incorporate greywater in the design
4. Get some advice
  • You should have experienced greywater professionals such as WaterCraft look over your plans
  • We can confirm that the planned system layout is practicable and can help your builder with any design or installation details
  • Shape and size of your various garden areas is important and WaterCraft can advise that areas planned to be irrigated with greywater are both an appropriate size for the amount of water produced and are permissible under the Code of Practice (width, proximity to walls and paths, pools etc)

Is it Worthwhile?

We plan on each occupant of an average Perth home producing around 100 litres of reusable greywater per day, of which most (60%) comes from the bathroom. That's nearly 3000 litres/week of water for a family home! Of course we’re really more interested in how much of our garden that could irrigate, and for a 4-person household that translates into an area of at least 60sqm in mid-summer depending on how waterwise your plants are.

Small Blocks

If you're building a new family home on a block of 350sqm or smaller then you're not going to have much garden. A small 'laundry-only' system may well provide enough water for the areas that need to be irrigated, and a system designed to take all the greywater may be overkill.
If insufficient green area is available, then the amount of greywater diverted to the garden will have to be reduced - e.g. by being selective with the sources of water or using a timer to cut operating hours.

Large Blocks

At the other end of the scale, you're unlikely to have sufficient greywater to irrigate all the garden on a large block and especially one with a lawn. Target the greywater on trees and selected beds to reduced the demand for scheme water.

The Verge

Unfortunately using greywater on ‘your’ verge is not permitted...because it’s public property and therefore not permitted under Dept. of Health regulations.


A Greywater Diversion Device (GDD) is licensed by your local Council for your specific property, who will check that:

  • The irrigation area is appropriately sized for the size of the house and expected number of occupants (based on the number of bedrooms) - so if you have a 5 bedroom house with only two occupants then the area that can be adequately watered with greywater would need to be scaled down.
  • The design of the irrigation area takes account of the various setbacks (from buildings, boundaries, paths, pools etc) to ensure that water doesn't pool on hard surfaces or run off onto neighbouring properties
  • The equipment used is approved by the WA Dept of Health

WaterCraft will ensure all these criteria are met and can prepare the plans and application for the 'Permit to Use' on your behalf. Most Councils charge a statutory amount for issuing a permit, which is $240 in 2017. Some Councils waive the charge, and others repay it.

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