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How Building Certification Works in New South Wales

A guide to the NSW building certification process, including principal certifiers, registration classes, complying development, and BASIX requirements.

Last reviewed: 2026-03-19

The NSW certification framework

Building certification in NSW is governed by the Environmental Planning and Assessment Act 1979 and the Building and Development Certifiers Act 2018. All building work that requires a development approval or complying development certificate needs a registered certifier to oversee compliance.

NSW uses the term "registered certifier" for practitioners who assess building work against the National Construction Code (NCC) and state legislation. They issue construction certificates, conduct mandatory inspections at critical stages, and provide occupation certificates when building work is complete.

Principal certifier role

Every building project in NSW that requires certification must have a principal certifier appointed before work begins. The principal certifier oversees the entire project, coordinates inspections at mandatory hold points, and takes responsibility for the compliance of the building work. The term replaced "principal certifying authority" in 2020.

The principal certifier issues the construction certificate (authorising construction to proceed) and the occupation certificate (authorising the building to be occupied). They must be notified before work commences and before certain critical stages of construction.

Registration classes

NSW Fair Trading registers certifiers across several classes. Class A1 can certify all building types without restriction. Class A2 is limited to Class 1 and 10 buildings (houses, sheds, pools). Class A3 covers residential and some low-rise commercial work. Class A4 handles subdivision certification only.

Council certifiers have corresponding classes (C1, C4, C10, C13). Class D1 covers principal certifier functions only, and Class E1 covers building inspectors. Always verify your certifier holds the correct class for your building type.

Complying development certificates (CDC)

NSW offers a fast-track approval pathway called complying development. If your proposed building work meets specific predetermined standards for your zone, a registered certifier can issue a CDC that combines planning and building approval into a single certificate, bypassing the need for a full development application through council.

CDCs are available for many standard residential projects including new houses, alterations, additions, and secondary dwellings (granny flats). The process is typically faster and cheaper than the standard DA pathway. Your certifier can advise whether your project qualifies.

BASIX requirements

The Building Sustainability Index (BASIX) is a NSW-specific sustainability requirement for residential buildings. Before a construction certificate or CDC can be issued, you must obtain a BASIX Certificate that demonstrates your design meets targets for thermal comfort, energy use, and water consumption.

Your certifier verifies that the building plans include the specific BASIX commitments (insulation levels, hot water system type, water-efficient fixtures, rainwater tanks) and checks during inspections that these commitments have been physically installed as specified.

Official Sources

Verify the information in this guide against these official government resources.

Frequently Asked Questions