Green Star Homes Resilience Guide
Water efficiency supports the Resilient outcome within Green Star Homes by reducing potable-water demand and coordinating fixtures, appliances, rainwater systems and outdoor water use across repeatable home designs.
Green Star Homes is a voluntary residential certification pathway structured for eligible volume home builders. Its requirements bring energy, health and resilience measures together across repeatable home designs and individual completed dwellings.
Within that framework, water efficiency is not established by one isolated product. It depends on the relationship between water-using fixtures, appliances, outdoor demand, any alternative water supply and the specifications ultimately delivered during construction.
This guide focuses on water efficiency as a Green Star Homes framework and evidence issue. Broader residential compliance, site-water and stormwater pathways remain separate. For the complete certification context, visit the Green Star Homes Knowledge Hub.
In Brief
Water Efficiency Is a Coordinated Residential Outcome
Reduce Demand
Water-efficient showers, taps, toilets and appliances can reduce routine potable-water use without relying on occupant behaviour alone.
Coordinate Supply
Where rainwater or another alternative supply is included, its catchment, storage, connections and intended uses must be practically resolved.
Verify Delivery
Product selections, drawings and construction records must support the water strategy represented in the applicable Green Star Homes submission.
A water strategy is therefore strongest when it can be repeated across a builder’s product range, controlled through specifications and confirmed in the completed home.
Resilient Outcome
Where Does Water Efficiency Sit Within Green Star Homes?
Green Star Homes is organised around Positive, Healthy and Resilient outcomes. Water efficiency sits most directly within the Resilient territory because it reduces pressure on potable-water supplies and supports homes that can respond more appropriately to drought, heat and changing climate conditions.
The water response also interacts with other parts of the home. Hot-water demand affects operational energy. Landscape decisions influence heat and irrigation demand. Rainwater infrastructure affects the roof, site plan, plumbing and maintenance strategy.
These relationships do not turn water efficiency into a general whole-home sustainability topic. The purpose of the water workstream is to establish and document a credible reduction in water demand within the applicable Green Star Homes framework.
Residential Water Strategy
Which Measures Can Support Water Efficiency?
Everyday Fixtures
Showers, Taps and Toilets
Efficient sanitary fixtures reduce daily water use across frequently repeated household activities and can be controlled through standard product specifications.
Water-Using Appliances
Dishwashers and Washing Machines
Where appliances form part of the builder’s scope or framework evidence, their water-rating information should align with the assessed product schedule.
Alternative Water Supply
Rainwater Harvesting
Roof-water capture can reduce mains-water demand where tank capacity, connected catchment and nominated reuse are coordinated as part of the design.
Outdoor Demand
Climate-Appropriate Landscaping
Plant selection, irrigated area, soil, shade and irrigation controls can influence the ongoing water demand associated with the home.
Design Control
Repeatable Specifications
Standard schedules and controlled substitution processes help maintain water-efficiency outcomes across multiple designs and completed homes.
Construction Evidence
Confirm the Installed Outcome
Certificates, schedules, invoices, photographs or other records may be needed to confirm which products and systems were installed.
Product Performance
How Do WELS Ratings Support the Water Strategy?
Australia’s Water Efficiency Labelling and Standards scheme provides standardised water-efficiency information for regulated products such as showers, taps, toilets, dishwashers and washing machines.
The star rating allows products within the same category to be compared, while the label also records the applicable consumption rate, such as litres per minute, litres per flush or litres per wash.
Within a Green Star Homes product range, WELS information can help establish measurable fixture and appliance specifications. The evidence should identify the products or minimum performance level relied upon by the applicable assessment.
A generic note stating that fixtures will be water efficient may not provide the same control as a coordinated schedule with identifiable ratings, product information and an approved substitution process.
Rainwater Coordination
A Rainwater Tank Is More Than a Storage Volume
A rainwater tank can support lower mains-water demand, but its contribution depends on the system surrounding it. Storage capacity alone does not explain how much roof water can be collected or how regularly the stored water will be used.
Confirm the connected catchment. The roof areas and downpipes supplying the tank should be identifiable and achievable within the design.
Define the intended uses. Toilet flushing, laundry or outdoor use should only be relied upon where the required plumbing and controls are included.
Coordinate the physical location. Tank access, pump requirements, overflow, maintenance and conflicts with private open space should be resolved early.
Maintain document alignment. The assessment, architectural plans, hydraulic information and final construction records should describe the same system.
Outdoor Water Demand
How Can Landscaping Influence Water Efficiency?
Outdoor water demand can become significant where homes include extensive lawns, high-water planting or irrigation systems that do not respond to the local climate. Landscape design should therefore be considered as part of the water strategy where it falls within the project scope.
Climate-appropriate species, reduced irrigated area, improved soil, mulch, shade and grouped planting can help reduce ongoing demand. These decisions can also support a more durable landscape during hotter or drier conditions.
The level of control available to a volume builder should be made clear. A standard front-landscape package, homeowner-selected garden or future landscape by others may each require a different evidence response.
Landscape commitments should only be included where they can be consistently communicated, delivered and retained within the applicable Green Star Homes pathway.
Certification Evidence
How Is the Water Strategy Carried Through Certification?
During the Green Star Designed assessment, the builder’s water strategy may be represented through standard specifications, product schedules, drawings, calculations and documented delivery processes applying to the eligible design or product range.
The completed-home pathway then requires evidence appropriate to the individual dwelling. The submission should demonstrate that the fixtures, appliances, tanks, connections or other relevant measures relied upon by the assessment were delivered on that project.
Substitutions need particular attention. A product may appear visually similar while having a different WELS rating or consumption rate. A tank may retain the same capacity while losing a required connection or reuse function.
Evidence collection should therefore be integrated into procurement, construction checks and quality-assurance procedures rather than reconstructed after the dwelling is complete.
NSW Compliance Boundary
How Does Green Star Homes Water Efficiency Relate to BASIX?
BASIX is a separate New South Wales residential planning and compliance pathway. Its water section may establish project commitments relating to fixtures, appliances, rainwater systems, landscaping, pools or other features depending on the development.
Those commitments can provide useful supporting information where a NSW home is also progressing through Green Star Homes. However, a BASIX water outcome does not automatically demonstrate the complete Green Star Homes requirement or completed-home evidence pathway.
The two workstreams should use consistent project assumptions. Fixture ratings, appliance selections, tank capacities and connected uses should not conflict across the BASIX Certificate, Green Star Homes submission, plans and specifications.
Outside New South Wales, the relevant state, territory and approval requirements should be reviewed separately.
Site-Water Boundary
Water Efficiency Is Not the Same as WSUD or Drainage Design
Green Star Homes water efficiency primarily concerns household and residential water demand within the applicable certification framework. It should not absorb the separate technical territory of site-wide stormwater treatment, detention, drainage or water-sensitive urban design.
A rainwater tank may appear in both a household water strategy and a site-water assessment, but the purpose of the evidence can differ. One pathway may consider potable-water substitution, while another considers runoff treatment, flow or broader site outcomes.
Larger developments, planning submissions or constrained sites may therefore require a separate hydraulic, stormwater or WSUD scope even where Green Star Homes water measures have already been defined.
Early Project Coordination
What Should the Builder and Project Team Clarify?
Product-Range Baseline
Define the fixture, appliance and alternative-water assumptions applying to the assessed standard designs.
Optional Upgrades
Confirm whether customer selections or upgrade packages can alter the water performance relied upon by the framework.
Substitution Approval
Establish who checks WELS ratings and system requirements before an alternative product is accepted.
Documentation Alignment
Keep Green Star Homes evidence, architectural plans, hydraulic information, schedules and jurisdictional commitments consistent.
Construction Records
Determine which records will be collected to verify installed fixtures, appliances and water systems.
Operational Information
Provide appropriate homeowner information where operation or maintenance affects the ongoing performance of a system.
Common Misunderstandings
What Should Water Efficiency Not Be Confused With?
One efficient fixture does not establish a complete water strategy. The assessed outcome depends on the coordinated product range and applicable evidence.
A rainwater tank does not automatically prove water efficiency. Catchment, reuse, plumbing and delivery must support the claimed strategy.
BASIX water commitments are not Green Star Homes certification. They belong to a separate NSW compliance pathway.
Water efficiency is not the same as stormwater treatment. Household demand and site-runoff performance require different evidence.
A nominated product is not necessarily the installed product. Completed-home evidence must support what was delivered.
Green Star Homes does not remove local requirements. Plumbing, health, planning and water-authority obligations remain separate.
Frequently Asked Questions
Green Star Homes Water Efficiency FAQs
Why is water efficiency important in Green Star Homes?
Water efficiency supports the Resilient outcome by reducing potable-water demand and helping homes respond more appropriately to drought, heat and changing climate conditions.
Which household products influence water efficiency?
Common products include showers, taps, toilets, dishwashers and washing machines. Their applicable WELS ratings and consumption information can support measurable product specifications.
Does every Green Star Home need a rainwater tank?
The applicable requirements and project strategy should be checked rather than assuming one universal solution. Where a tank is relied upon, its catchment, capacity, connections, reuse and construction evidence must be coordinated.
Can landscaping affect the Green Star Homes water strategy?
Yes, where landscaping falls within the assessed project scope. Plant selection, irrigated area, soil, shade and irrigation systems can influence outdoor water demand.
Does BASIX water compliance satisfy Green Star Homes?
Not automatically. BASIX is a separate NSW compliance pathway. Its water commitments may provide supporting information, but Green Star Homes retains its own eligibility, framework and certification evidence requirements.
Is water efficiency the same as WSUD?
No. Residential water efficiency is primarily concerned with water demand and supply within the home and its immediate landscape. WSUD addresses broader site-water, runoff, treatment and landscape integration.
What happens if a specified fixture is substituted?
The replacement should be checked against the water-performance requirements relied upon by the assessment. A similar appearance or product type does not confirm an equivalent WELS rating or consumption rate.
How is water efficiency verified in a completed home?
The applicable completed-home submission may use product schedules, invoices, certificates, photographs and other construction records to demonstrate that the assessed measures were delivered.
When should the water strategy be developed?
The strategy should be developed while standard specifications, hydraulic requirements, tank locations, landscape scope and customer-selection processes can still be coordinated.
Related Guidance
Explore the Connected Residential Pathways
Last reviewed: June 2026. Green Star Homes is administered by the Green Building Council of Australia. WELS is an Australian Government initiative delivered in partnership with the states and territories. Current eligibility, product-performance and submission requirements should be confirmed against the applicable official framework guidance.
Green Star Homes Project Review
Does the Water Strategy Need Coordination?
Send the available product-range information, standard specifications, fixture schedules, rainwater strategy and certification objectives for an initial scope review. Certified Energy can help clarify how the water-efficiency evidence fits within the wider Green Star Homes pathway.
Send Your Project Documents
