BASIX help notes are designed to assist and guide you through the BASIX assessment tool. You will find that the help notes are linked to from the BASIX assessment tool in the form of question mark icons. You can also view the notes self directed. For ease of use we have also made the help notes accessible from the BASIX website. 

BASIX help notes are categorised under the following sections:



The Water section of BASIX aims to reduce the potable water consumption of all new residential developments. The benchmark is 90,340 litres of water per person per year (or 247 litres per person per day), which was the average potable water consumption of a pre-BASIX home.

The water reduction target ranges from 40% to 0% depending on the climatic zone. The 40% reduction target applies to 90% of new residential development and 98% of high-growth areas. The BASIX targets are determined from data provided by state and federal energy and water utilities, as well as long-term climate data from the Bureau of Meteorology.

Water consumption and savings will be assessed based on:

• landscaping;

• fittings and fixtures;

• alternative water sources and how they are used;

• pools and outdoor spas;

• other energy uses; and

• central systems and common areas.

Reducing the demand for hot water by installing efficient showerheads and taps will also reduce the energy required for water heating and improve your score in the Energy section..


BASIX assesses fittings, fixtures and appliances based on:

WELS water efficiency rating for all showerheads;

WELS water efficiency rating for all toilets;

WELS water efficiency rating for all kitchen and bathroom taps; and

for multi-dwelling unit developments (but not groups of single dwellings or townhouses), the water efficiency of water-using appliances.

Please note that the rating selected MUST match the rating of the fittings and fixtures installed in the development and this needs to be signed off by the certifier.

In the BASIX multi-unit tool the values selected will be applied to all dwellings in the dwelling type. If you wish to apply values to specific dwellings, select them individually using the checkbox to the left of the dwelling numbers.


• rainwater– collected from roof areas and stored in a rainwater tank;

• stormwater– collected from trafficable surfaces and stored in a stormwater tank;

• greywater– diversion and treatment systems can be used to collect and re-use wastewater from the bathroom and laundry;

• private dams (single dwellings only)– for toilet flushing, laundry, garden irrigation;

• reticulated alternative water supply (approved multi-dwelling developments only)– recycled wastewater supplied by a water authority or central authority via a reticulated system to individual lots for non-potable use;

• central on-site recycled water systems (multi-dwelling developments only)– for toilet flushing, laundry, garden irrigation; and

• hot water recirculation and diversion– collecting water from hot water fittings until the water reaches the desired temperature.

For each water use in the development, you must nominate a water source. The source may be mains-supplied potable water or one of the recognised alternative water sources.

Alternative water sources are optional, but in most cases a dwelling will need to nominate an alternative water source in order to achieve the required water target.

Note: There are limits to alternative water use for some alternative water sources.

BASIX does not recognise the following water supplies as alternative water sources. Please refer to the relevant help notes for further information:

• Groundwater.

• River or 'Raw' Water

• Onsite Sewage Management Systems

BASIX takes into account the on-going water usage for any new pools or outdoor spas included in your development application. You can reduce the water use associated with a pool or spa by;

• Installing a permanent pool or spa cover

• Shading the pool or spa area

• Selecting a rainwater tank for top-up

See also Pools and Outdoor Spas (Energy Usage).

BASIX needs to know:

- the location of the pool (indoors or outdoors).

- the size (volume) of the pool or spa in kilolitres.

- whether the pool or spa has a cover and/or is shaded.

-if you will be using a tap connected to a rainwater tank for pool or spa top-up (selection found on the Alternative Water Details page).

In order to obtain a BASIX Certificate confirming compliance with the NSW Government's sustainability requirements, a residential development proposal is required to use up to 40% less potable water than the average home 'pre-BASIX' home benchmark of 90,340 litres of water per person per year or 247 litres per person per day.

The water target varies for different climatic zones in NSW. It ranges from 40 to 0 across depending on the location of the house or unit. See Water Target Zones.

Key facts

• No new home built in NSW will use more water than the current state average.

• The 40% water target covers 90% of new residential development, which represents 98% of NSW population growth.

• Developments in areas covered by the 0% target still need to reduce water consumption in order to meet the state average water use benchmark.

The BASIX targets are determined from data provided by state and federal energy and water utilities, as well as long-term climate data from the Bureau of Meteorology.

General tips for reaching water targets

• Select the highest WELS rated fittings and fixtures available for your development, including efficient showerheads, dual flush toilets, and flow regulators in your taps

• Install an alternative water supply, such as a rainwater tank and connect it for internal use (toilets and/or laundry).

• Install an alternative water supply for garden use and include low water use species as part of your landscaping plan.

• Include shading and a permanent cover for any pool or outdoor spa.

• There are a number of additional options available to multi-unit developments.





This information will help you fill out the project details section of the BASIX assessment tool:

Project address
Project type
Site details