There are multiple things to think about when building a new home and complying with the Building Sustainability Index (BASIX) is one of them. BASIX ensures that homes are built to be more energy and water efficient by setting clear sustainable housing targets for new homes developed in NSW. BASIX aims to deliver equitable, effective water and greenhouse gas reductions across the state.

Since the implementation of the BASIX initiative, the Department has been monitoring 100 BASIX compliant homes. Of these houses, when it comes to rainwater tanks, they have noted that every home has a rainwater tank, with the average size being 4000 litres and the majority of which will be plumbed to the toilet and laundry, as well as providing water for the garden.

Having a rainwater tank installed in your home allows you to utilise harvested rainwater in your home and garden. To ensure you take full advantage of this free water supply, there are a number of things for you to consider, helping you make sure you are getting the most from your water system. Read our article on top suggestions to utilise your rainwater tank (hyperlink our top suggestions in utilising your rainwater tank with

BASIX applies to all residential dwelling types and is part of the development application process in NSW. It is an integrated part of the planning system, implemented under the Environmental Planning and Assessment Act. BASIX is assessed online using the BASIX Environmental Tool. The tool checks elements of a proposed design against sustainability targets.

The Energy section of BASIX aims to reduce the greenhouse gas emissions of all new residential dwellings.

Energy consumption and savings will be assessed on:

  • Hot water systems
  • Heating and cooling
  • Ventilation
  • Lighting
  • Pools and spas
  • Alternative energy sources
  • Other energy uses
  • Central systems

The Water section of BASIX aims to reduce the potable water consumption of all new residential developments.

Water consumption and savings will be assessed on:

  • Landscape
  • Fittings and fixtures
  • Alternative water sources and how they are used (this includes rainwater tanks)
  • Pools and outdoor spas
  • Other energy uses
  • Central systems and common areas.

The aim of this is to reduce greenhouse gas emissions and set water reduction targets. It is a requirement of the NSW Government that all new housing developments submit a BASIX certificate, and it should be submitted to your local Council in the design phase of development.

How do you obtain a BASIX Certificate?

The BASIX online tool is simple to use and can be completed either by yourself or your builder. In order to obtain a BASIX certificate for your proposed development, you will need to complete the sustainability assessment using the BASIX assessment tool.

How the assessment tool works:

  • The BASIX assessment tool analyses data relating to the design of your proposed house and determines how this scores against water and energy targets. The dwelling design must meet specific targets before the proposed development can be issued with a BASIX certificate.
  • Once the design complies with BASIX, a BASIX certificate listing the sustainability commitments can be printed and submitted with the development application.

Installing a rainwater tank and complying with BASIX can benefit you and will kick start your dream home in the positive direction. By building a sustainable home, you’re helping the environment and your wallet by saving money through the reduced household energy and water bills.