BASIX certificate in NSW explained: when you need one

BASIX is the NSW sustainability requirement for homes. Here is when it applies and who prepares it.

What BASIX is

BASIX, the Building Sustainability Index, is the NSW Government's tool for setting water and energy targets for homes. A BASIX certificate is part of the approval documents for a new home or a qualifying alteration.

When you need one

• New homes: a BASIX certificate is needed when you lodge a development application for a new home.
• Alterations and additions: the BASIX site says a certificate is needed for any alteration or addition costing $50,000 or more to an existing home.
• Swimming pools: for pool work lodged as an alteration, the BASIX site says compliance applies only if the pool holds more than 40,000 litres. Other official material says 40,000 litres or more, so confirm a borderline pool with your council.

What the pool part asks

For a pool, BASIX asks for the pool's location (indoors or outdoors), its volume in kilolitres, whether it has a cover or shade, and whether the top-up water comes from a rainwater tank.

Who prepares it

A BASIX certificate is prepared using the online BASIX tool, usually by an accredited consultant who works from the design. A building designer coordinates the result into the drawings. Building designers who coordinate BASIX use an external accredited consultant for the certificate.

Why it matters at design stage

BASIX targets can affect windows, shading, hot water and materials, so the earlier it is considered the fewer changes are needed. See DA vs CDC drawings.

Common questions