Josh’s House – greywater for a new home in Fremantle

A case study in sustainable housing, Josh’s House is a 3 bedroom, 2 bathroom family home in the Fremantle suburb of Hilton. Josh’s House has a 10 star energy efficiency rating, harvests and recycles water as part of an integrated approach to reduce scheme water demand and has productive garden areas.

System make and model

A direct diversion system called the Grey
Flow by Advanced Wastewater Systems was installed. It is a pumped system that has the advantage of an automatic filter back flush device to reduce maintenance. It also has a very practical two-stage installation process which begins with the installation of a sump and dual interceptor unit (referred to as the ‘Builder’s Kit’) as part of the initial drainage plumbing works, followed by the installation of the pump, controls and irrigation at a later stage during landscaping.

AWWS Greyflow

A greywater direct diversion system called the Grey
Flow by Advanced Wastewater Systems (AWWS).

Irrigation area

The greywater system is based on an occupancy rate of four people, generating
up to 100 litres per day in the bathroom and laundry, that’s 400 litres in total per day. Located on the sandy soils of Swan Coastal Plain, greywater is applied at a maximum rate of 10mm of water per day over an area of 40m². This area includes fruit trees, shrubs and other ornamental plantings. The greywater is disbursed via purple coloured substrata dripline irrigation, which is installed on the surface
of the soil and covered with a 100mm layer
of mulch. The dripline has drippers spaced at 300mm intervals along the length and the driplines spaced at 300mm apart. The drippers are high-flow, clog resistant and designed to be self-flushing. The dripline is installed between a supply pipe and a collector pipe. A manual flush valve has been fitted to the collector pipes on each bed to allow for the occasional flushing of the irrigation lines to clear out any muck that may accumulate. A vacuum breaker valve has also been included at the highest point of the irrigation line. This allows air to enter through the one-way valve as the water drains out of the line avoiding the potential for dirty water being sucked back through the drippers that can lead to them becoming blocked with grit. Greywater irrigation drip lines are setback from paving, retaining walls, neighbouring properties and buildings to comply with the Code.

Cost of installation of Greywater System

Approximately $7,000 which included the complete system, all labour, plumber’s charges and power point installation, all irrigation
to lawn and garden beds, Council fees and inspection, testing and commissioning, and handover to client.

Approvals process for Greywater

Coordinated with building construction program.

GndW = Ground Water
GW = Greywater
RW = Rainwater
MW = Mains Water


Reduction in scheme water consumption

Outcome/Water savings

The alternate water systems installed at Josh’s House, including a rainwater tank, bore and greywater, significantly reduce the demand for scheme water, resulting in 92% reduction in scheme water consumption than the average Perth household. Source: Byrne (2017)

Indicative costs
The table below sets out indicative costs to supply and install various types of greywater reuse systems for a typical home. It includes cost ranges for pumped greywater diversion

devices (GDD) and also greywater treatment systems (GTS) for both garden-only and in- house use. Installations outside the Perth metropolitan area may also incur additional costs, for example due to travel and freight charges.

Greywater Prices

TypeGDD (pumped)GTS
Purchase Price $750 (6) - $2,500 (7)$8,000-$10,000
Installation (unit only)(8)$250-$1,000 $1,500-$4,000
Install dripline (40-50m) $750-$1,000 N/A as used in-house or to sprinklers
Retrofit plumbing (1-2 fixtures)(9)$400-$1,000$400-$2,000 (10)
Greywater-ready plumbing (laundry, new house) $200-$500 See below
Greywater-ready plumbing (whole house, new) $750-$1,500 $750-$1,500
LGA fees (11) $240 $240
Consultancy fees to assess sites and prepare application to council with plans $100-$500 $100-$500
(6) A smaller system scaled for a laundry or similar
(7)  A larger system that would handle the whole house
(8)  Scale of installation costs will vary with unusual soil or ground conditions and the size of the greywater system
(9)  There are often site-specific factors such as ease of access to the drainage lines on retrofits
(10)  Additional cost for the GTS is due to the pump and pressure line requirements.
(11)  Some council waive or reimburse the fee, which is set by State Government.

I love using Grey water in my garden because it allows me to minimise the use of scheme water in our garden watering regime with only small changes to the type of cleaning products we use in our laundry and bathroom. It also allows me peace of mind every time I take a shower knowing the water isn’t just going down the drain but directly into my beloved garden. 

Andrew Beck
Sustainable Garden Design Perth

Having Greywater go to my garden means my plants get watered every day of the year when I’m home. The water savings in summer are huge. Installing a greywater system at my own new build was a must, along with a Rainwater tank. Putting these systems in during the build process is easy compared to retrofitting, and generally cheaper. ‘Water Capture’ sell, install and service Greywater systems in Perth. 

Mark Harland
Water Capture

WaterCraft service a lot of greywater systems across the metro area and see many gardens thriving on the use of greywater. Frequent watering with traces of soap and nutrients works really well for plants on poor sandy soils. But just as you wouldn’t expect your mains water retic system to run for years without any attention, don’t expect your greywater system to keep running without a service!

Gareth Almond

About The Author


Greywater & Wastewater Industry Group. We are a group of water industry professionals who are active in the design, research, manufacture, installation and servicing of greywater and wastewater treatment systems. GWIG is a non-profit organisation which was formed in late 2010 in order to provide a united voice for a WA industry that is largely unsupported and under-acknowledged for the important work that it does.