WA's wastewater, Rainwater & Irrigation Professionals
Greywater Reuse Systems
Unit 1 / 18 Wandeara Crescent | Mundaring WA 6073

Our Grey Water Filter systems (GRS V & H Filters) are diversion systems, not treatment systems, therefore cannot be used to flush the toilets. Untreated greywater is only authorised to be used to water the gardens (not root vegetables) via subsurface irrigation method (covered by mulch) or under lawns. An explanation of each system is detailed below.
Recommendation of a greywater system best suited to your property and requirements is site specific, it is dependent on a number of factors, eg; the size of your roof, how many bedrooms the property has, how large the garden area is and the clients specific greywater reuse requirements. 

GRS V & H Filter Systems

The GRS H Filter system is intended for use of the entire house, e.g. laundry and bathrooms, where as the GRS V Filter system is most often used for a single fixture e.g. laundry/trough.

Installation, Pricing, Information and DIY Greywater Kits

We perform full installation if required, including all aspects of design and specifications for council applications. Typically the cost is anywhere between $5,500 to $7,000 dependent on site location. 

A quotation must be performed, please see Option 2 on our Consultancy page for more information.

Full installation includes all general labour to install system and irrigation, present at council inspection and handover to client. * Electrician and Plumbers fees are not included and all bills pertaining to the install, will be forwarded to the client to pay.

DIY - GRS Filter Kits

We also sell our GRS Filter systems as DIY kits where you would need to organise all council application/approvals, a licensed plumber to connect, electrician and install the entire system yourself.  

You can save a lot of money doing it this way! 

  • Click here to find out more about our Greywater Horizontal DIY Kit.

  • Click here to find out more about our Greywater Vertical DIY Kit.

GRS Filter Systems Explained

This in-line filter system is used to filter greywater from typically one source, such as from the laundry or bathroom, but can be used in a whole-of-house diversion. Greywater can contain a variety of substances, such as lint, grease, soil particles and hair, which can block the soil, subsurface drain system and dripline. Greywater needs to be filtered before it passes into the irrigation or infiltration area. The filter used is typically a 300 to 400 μm nylon fibre bag which is able to be easily removed via two moulded handles. 

The GRS Filter has a safety overflow device which enables wastewater to re-enter the existing treatment system should the need arise. Furthermore, a diverter valve enables the householder to manually turn on or off the diversion capability during winter or at other times. After filtration, the greywater is then passed into an approved subsurface drain system or dripline system where it can be absorbed by plants. 

Installation Requirements

The installation and connection of this filter system must be undertaken by a plumber licensed under the appropriate Plumbers Licensing Regulations found in each state. The plumber must obtain approval from the Sewerage Service Provider for any required connection or modification to the plumbing works connected to the sewer system. The installation must also comply with AS/NZS 3500:2 (2003).

The installation of any greywater reuse system must also be approved by the local government authority, and will require a formal application to be made to the Local Government. Contact the Environmental Health Officer/Inspector at your local council about their requirements and fees.

The specifications and installation procedure is found on the document “GRS Filter Installation and Specifications”. This document outlines how the filter bags are installed and removed. All other components are either moulded or glued in position. The rotary diversion valve is able to be unscrewed to enable changes to flow direction, and for cleaning.

Do’s and Don’ts, to ensure the maximum life of your GRS Filter system, the following are helpful suggestions:

  • Use environment-friendly soaps and detergents. Select washing powders or liquids which contain low levels of phosphorus and sodium. Generally, liquid laundry detergents have lower levels of salts than powders.
  • Greywater should only be applied as subsurface or substrata irrigation of plants. Greywater must not be sprayed onto edible (food) plants. While you can irrigate above-ground food crops, there should not be contact of any edible fruit or vegetable part with the soil.
  • Do not overuse bleaches, fabric softeners or washing products containing borax or chlorine. Try to minimise the use these substances, and purchase biodegradable products wherever possible.
  • Do not use greywater from the washing of nappies and/or soiled clothing.
  • Do not use greywater from any source if a member of the family has an infectious disease, such as diarrhoeas, intestinal parasites or infectious hepatitis.
  • Greywater must not be stored for any length of time. Stored greywater will turn septic and cause unpleasant smells.
  • Divert greywater from your system back into the sewer line during winter when your garden may not need additional watering.
  • Monitor plant and soil response to greywater irrigation. Some plants do not survive in alkaline or salty soil conditions.


A twelve months warranty, from the date of installation, is given on the GRS Filter, as well as any diverters supplied by Water Installations Pty Ltd.

What is Greywater?

Greywater is the wastewater stream from all sources other than the toilet (toilet water is often called blackwater or sewage). It is called greywater because it appears this colour, or turns grey after a short storage period.

Why recycle greywater?

The average Australian household uses about 800 L per day for both inside and outside use. Table 1 shows the approximate volume for each use. Typical values for the volume of greywater produced ranges from 100 to 200 litres per person per day. Table 1 Approximate volume of greywater from household sources.

Volume per Day (L) 
 Greywater  350
 Outside / Watering  300
 Bathroom  185
 Laundry  115
 Kitchen  50

Greywater can be reused in a variety of ways, such as watering garden plants and for toilet flushing. Watering our gardens with greywater can be easily achieved. Water is too valuable a resource to waste, and any endeavour to reduce freshwater consumption or reduce wastewater disposal and treatment (and the energy this consumes) should be encouraged. More importantly, we should endeavour to reduce our water consumption by instigating a range of strategies which include installing reduced-flow shower heads, using water-efficient washing machines, turning off the tap when cleaning your teeth, and taking shorter showers.

Health concerns

Greywater contains a range of organisms which may cause disease (pathogens). Greywater is not allowed to be used in ponds or for above-surface irrigation systems due to the risk of mosquito breeding and contact with human skin and possible pathogen transfer. Many pathogens such as bacteria (e.g. faecal coliforms) and protozoans (e.g. Giardia) may be present in some greywater sources.

Greywater also contains bacteria and other microscopic organisms which feed on the nutrients in greywater, causing the wastewater to smell after a day or two. High levels of nitrate and phosphate may be beneficial to many plants, but can be detrimental to humans if ingested.

What greywater sources are best to reuse?

Greywater produced by a household can vary according to the number of occupants, and water usage patterns of the occupants.

Laundry water is probably the easiest to access as the plumbing often passes through the house wall, and a diverter can be installed.  On average it can contribute from anywhere between 30-40% of the total greywater volume.  Wastewater from the laundry varies in quality from each wash and can be contaminated with lint, oils, greases, chemicals, soaps, nutrients and other compounds. 

Bathroom water is also suitable, but it may not be easily accessible as drainage normally occurs below the slab and may be close to the toilet water source. It may need to be collected and pumped to the infiltration area. On average it can contribute from anywhere between 50-60% of the total greywater volume.  Bathroom greywater can be contaminated with soaps, hair, shampoos, toothpaste, lint, body fats, oils and cleaning products. 

Kitchen greywater (and dishwasher water) generally should not be reused as this can contain oil, fats and food scraps, which do not break down easily and can clog irrigation pipes. On average it can contribute from anywhere between 5-15% of the total greywater volume.   The detergents and cleaning products may be alkaline and contain chemicals that are harmful to soil structure, plants and groundwater. 

Greywater reuse strategies

Greywater from sources such as the laundry and bathroom is allowed to be used in a subsurface drain system for plant irrigation. This includes sewered blocks, provided the appropriate application (and fees paid) is submitted and approved by the Health Department (via the local council) and (sometimes) the Water Corporation or Sewerage Service Provider (who are responsible for sewerage).

Greywater cannot be used to irrigate a below-ground vegetable garden, but can be used on nearby/below fruit trees, lawn areas and on other plants (both exotic and native shrubs and trees). It is also possible to manually bucket greywater from the laundry trough to water plants. Placing greywater in the root zone of plants is the most effective way to ensure maximum uptake of both the water and the range of nutrients which are available in greywater. A word of caution: many native plants (e.g. the family Proteaceae such as grevillea, banksia and hakea) are susceptible to high levels of phosphate. Some introduced (exotic) plants, such as azaleas, camellias and gardenias, do not like the alkaline nature of some greywater sources. It is best not to use greywater on any of these types of plants.

Click here to see a list of plants best suited to infiltrate greywater.

A number of different subsurface drain configurations are shown on plans developed by Greywater Reuse Systems (GRS). GRS also sells a filter and a number of different greywater diverters.

GRS generally installs untreated greywater dispersal/diversion systems (Primary Treatment). Treated greywater systems (such as Grey Wise) are also available from us, and there are stringent monitoring and nutrient and pathogen content standards to be achieved.

Greywater should first pass through a filter and/or settling tank before dispersal in an infiltration area. This removes coarse material (e.g. hair, soap flakes, sand and lint) which could block the draincoil pipe or soil, or both.

An overflow safety device is required to divert greywater either back into a sewer line or into an existing wastewater treatment system (septic tank and leach drain) should problems arise. A vent, with a screened cowl, will need to be installed to prevent accumulation of foul air. Furthermore, there are restrictions on the location of greywater reuse systems within a property. For example, large tanks and trenches must be at least 1.2 m from boundaries and/or buildings. No greywater from one property is allowed to flow onto any neighbouring property.

 No. Bedrooms
Laundry* Bathroom Total Flow  Irrigation Area 
 2 or less
 120  180   300   60
 3  160  240  400  80
 4  200  300  500  100
 5+  240  360  600  120

Consultations & Quotations

It is best to schedule an on-site consultation where you will receive site specific, one-on-one expert advice.  Click here >


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Unit 1 / 18 Wandeara Crescent | Mundaring WA 6073