Plumbing Code of Australia: NCC Volume Three, TradeForm Knowledge

What it is

The Plumbing Code of Australia, known as the PCA, is Volume Three of the National Construction Code. It is published by the Australian Building Codes Board (ABCB) and adopted by each state and territory. The PCA sets the minimum technical requirements for plumbing and drainage installations across Australia and New Zealand jurisdictions that reference it.

Volume Three sits alongside Volume One (commercial building) and Volume Two (residential building). Where Volumes One and Two cover the structure, fire safety and accessibility of a building, Volume Three covers everything that moves water, gas and waste through it.

Scope of NCC Volume Three

The PCA applies to plumbing and drainage installations in new buildings and to alterations, additions and replacement work in existing buildings. The current edition is NCC 2022 Volume Three, which has been progressively adopted by states from 1 May 2023, with some state-specific transition arrangements.

Systems covered

Water services (cold, heated and non-drinking)
Sanitary plumbing and drainage
Stormwater drainage
Heated water services
On-site wastewater management
Excessive noise from plumbing systems
Cross-connection control and backflow prevention

Gas installations are covered separately under the AS/NZS 5601 gas installation standards, although the PCA references gas where it interacts with water heaters and other plumbing fixtures.

Structure of the PCA

NCC Volume Three uses the same performance-based format as the rest of the NCC. Each section has Performance Requirements that state the outcome, and Deemed-to-Satisfy (DTS) Provisions that show one way to meet those outcomes. Compliance can also be achieved through a Performance Solution.

Sections of Volume Three

Section A: Governing requirements
Section B: Water services
Section C: Sanitary plumbing and drainage
Section D: On-site wastewater management
Section E: Heated water services
Section F: Excessive noise
Section G: Stormwater drainage

State-specific variations are included as appendices for jurisdictions including New South Wales, Victoria, Queensland, Western Australia, South Australia, Tasmania, the Northern Territory and the Australian Capital Territory.

Relationship to AS/NZS 3500

The DTS Provisions of NCC Volume Three reference the AS/NZS 3500 Plumbing and drainage series as the primary technical standard. Following AS/NZS 3500 is the standard route to compliance for most residential plumbing work.

The AS/NZS 3500 series

AS/NZS 3500.0 Glossary of terms
AS/NZS 3500.1 Water services
AS/NZS 3500.2 Sanitary plumbing and drainage
AS/NZS 3500.3 Stormwater drainage
AS/NZS 3500.4 Heated water services
AS/NZS 3500.5 Domestic installations (housing provisions)

NCC 2022 Volume Three updated its references to Parts 1, 2 and 4 of the AS/NZS 3500 series from the 2018 editions to the 2021 editions. The 2021 editions are the current call-up for Deemed-to-Satisfy compliance.

How the PCA is enforced

The PCA itself is a model code. It only has legal force when each state or territory adopts it through its own legislation. Each jurisdiction has its own plumbing regulator that licenses plumbers, inspects work and signs off completion paperwork.

State plumbing regulators include the Victorian Building Authority, NSW Fair Trading, the Queensland Building and Construction Commission and the Plumbers Licensing Board in Western Australia. A licensed plumber must perform notifiable plumbing work and lodge a compliance statement after the work is finished.

Common compliance failures

Residential plumbing failures typically come from three areas. The first is incorrect pipe sizing or material selection that does not match AS/NZS 3500.1 minimum diameters. The second is failure to install required backflow prevention for the assessed hazard level. The third is mixing potable and non-potable water lines without separation and labelling.

WaterMark approval is also a requirement. All plumbing products used in installations covered by the PCA must carry the WaterMark if they are listed in the WaterMark Schedule of Products. Using non-WaterMark product is a non-compliance even if the installation method is otherwise correct.

Where to find the PCA

The full PCA is available free to read at ncc.abcb.gov.au. The ABCB also publishes handbooks and guidance documents that explain how Performance Solutions can be developed for plumbing work that does not follow the DTS path.

Plumbing Code of Australia: NCC Volume Three Overview