Green Steel Homes

Water Sub-system

The preliminary design for the water sub-system in a GSH home is almost completed.  Click on the image below to enlarge the diagram.

GSH Water Sub-system

The retail cost of this system, excluding plumbing and tapware, is less than $30,000 (including government rebates).  However, once we start producing homes and forming relationships with suppliers and manufacturers, this cost will come down.  Prices are also expected to drop as a result of increasing demand for environmental technology over the coming years.

While this may seem a high price, consider the benefits:

  • plenty of free water for your house and garden
  • ultra-low water consumption
  • pure drinking water
  • chlorine-free shower water
  • zero load on the state water supply
  • energy savings

If the state water supply cannot keep up with demand over the coming decades, you won't have to worry, because you'll have plenty!  (Your biggest problem will be the neighbours coming over with buckets!)

Water is currently free or cheap, depending on where you are.  However, considering drought conditions and the rapid growth of Australia's population, it is unlikely to remain that way.  Furthermore, most water supplies, whether from town water, bore water or rain water, is tainted in some way by chemicals or pathogens.  A modern purification system is essential for good health, no matter where the water comes from.



Description Price Supplier
Blue Mountain Gutter Mesh ($18/m x 15m) $270 Rain Harvesting
First flush diverter $40 Rain Harvesting
23639L Water Tank $3,640 Clark Tanks
Davey KRB60 RainBank Pump $862 Davey
Rain Alert $180 Rain Harvesting
270L Quantum Heat Pump Hot Water System
($3,395 less $772 federal govt. rebate)


Quantum Energy
Whole of house carbon filter plus Single Undersink Purifier $2,500 Pure Water Systems
Perpetual Water - Home grey water recycler with 3000L tank
$12,600 Perpetual Water
Enviro Save Water System Thermo Valves (6 @ $198 ea.) $1,188 Enviro Manufacturing Co.
Haier HWM1260K Washing Machine $699 Haier
Rota-Loo 950 with 2 fibreglass pedestals
Environment Equipment
TOTAL $28,567 Green Steel Homes


Water Usage

The following table shows estimated water usage (in litres) for a family of 4 in this home.  The amount for gardening is a total guess and depends on the size of the garden.


  Daily Weekly Monthly Yearly
Drinking 12 84 364 4,368
Cooking & Cleaning 8 56 243 2,912
Showers 180 1,260 5,460 65,520
Toilet 0 0 0 0
Laundry 21 144 624 7,488
Car wash 2 12 50 600
Gardening 86 600 2,600 31,200
TOTAL 308 2,156 9,341 112,088


This house is extremely water efficient, mainly because of the low water requirements of the washing machine (36 litres per wash) and toilet (0 litres).  The total requirements of the house, including water for gardens, should be less than 120,000 litres per year.  The grey water recycling system recycles water from the showers and laundry, a total of about 200L per day, which is more than enough for the laundry, car washing and gardens.  The rainwater tank therefore only needs to supply water for drinking, cooking, cleaning and showering, a total of about 200L per day or 6,070L per month, which means it can store enough water for almost 4 months supply.  In theory the mains water should never be required, however we connect it as a precaution.


Water Quality

Water quality from either mains supply or rain water tanks is rarely suitable for drinking.  This house includes 4 levels of filtration and provides extremely pure water.

1.  Blue Mountain Gutter Mesh has approximately a 5mm aperture and filters leaves, twigs, gumnuts, large insects, frogs, rats and mice from entering the water supply.  It also prevents mosquito breeding in the gutters, since they remain clear and warm pools cannot form, and reduces the possibility of gutters catching fire.

2.  The Clark Tanks come with very fine mesh (<1mm aperture) which prevents mosquitos and small particles entering the tank.

3.  A Pure Water Systems "Whole of House" carbon filter removes "chlorine, trihalomethanes, chemical pollutants and associated tastes and odours".  This has been used for the whole water supply to the house, rather than drinking water only, mainly so that chlorine is not present in shower water.

4.  Finally, an under-sink filter removes bacteria and pretty much everything else you can think of.  This provides high-purity water for drinking and cooking.




Proceed to Ecovillage Projects.