BCA vs PCA: which NCC volume applies to your project?

TL;DR

The BCA and PCA are not competing codes: the BCA (Volumes One and Two of the NCC) governs building work; the PCA (Volume Three) governs plumbing and drainage. Both apply on every residential build. The split matters most when you’re scoping inspections and defect liability: a leaking shower is potentially both a waterproofing defect (BCA Volume Two H2) and a drainage defect (PCA Volume Three), so knowing which code the certifier uses to assess the work tells you who’s on the hook.

In plain English

The National Construction Code (NCC) is published in three volumes. The confusion between the BCA and PCA comes from how they’re named and who uses them day-to-day.

BCA (Building Code of Australia) is the name for the two building volumes:

Volume One: Class 2 to 9 buildings (multi-residential, commercial, industrial, public assembly)
Volume Two: Class 1 and 10 buildings (houses, duplexes, townhouses, sheds, garages)

PCA (Plumbing Code of Australia) is Volume Three. It covers plumbing and drainage for every building class, including Class 1 houses. Your licensed plumber references it; your Principal Certifying Authority (PCA, confusingly the same acronym) requires plumbing inspection sign-offs against it.

Both codes apply to most residential projects simultaneously. They don’t overlap: the BCA governs structural, fire, waterproofing, energy, and health/amenity provisions; the PCA governs water supply, sanitary drainage, stormwater, and gas (verified 2026-05-09: ABCB, NCC overview).

What it requires

Decision table: BCA or PCA?

Work type	Applicable code	Volume
Structural framing, footings, slabs	BCA	Two (Class 1) or One (Class 2+)
Fire separation between units or garage	BCA	Two H3 or One C
Waterproofing wet areas	BCA	Two H2
Energy efficiency (NatHERS, glazing, insulation)	BCA	Two H6
Livable housing design	BCA	Two H8
Balustrades and stair geometry	BCA	Two H5
Smoke alarms	BCA	Two H3
Water supply (pipes, pressure, backflow)	PCA	Three
Sanitary drainage (toilets, waste)	PCA	Three
Stormwater drainage	PCA	Three
Gas installation	PCA	Three
Plumbing ventilation	PCA	Three
Hot water system installation	Both	BCA Two H4 (amenity) + PCA Three (connection)

The “both apply” zone

A small category of work sits across both codes. Hot water systems are the clearest example: the BCA’s amenity provisions set minimum delivery temperature and flow requirements (Volume Two H4), while the PCA governs the physical pipe connections and backflow prevention (Volume Three). The certifier assessing a plumbing inspection and the certifier assessing the building inspection are often the same person, but they’re checking against different volumes.

Wet areas are another overlap zone. Waterproofing (shower recesses, laundry floors) is a BCA obligation under Volume Two H2, referenced to AS 3740. The drainage geometry (fall to waste, grate position) is a PCA obligation. A leaking shower can fail on the waterproofing spec (BCA) or the drainage spec (PCA), or both. In a defect dispute, knowing which code applies to which failure is important for directing the rectification scope to the right subcontractor (verified 2026-05-09: NCC 2022 Volume Two, H2 Damp and weatherproofing).

The PCA acronym clash

The same three letters mean two different things in this industry:

PCA as a code: Plumbing Code of Australia (NCC Volume Three)
PCA as a person: Principal Certifying Authority (the certifier who runs inspections on your job)

Both are in use daily. Context usually makes it clear, but if you’re reading a contract or compliance document and see “PCA”, check whether it’s referring to a document or a person.

What it doesn’t cover

Both codes together still don’t cover:

Planning and zoning requirements (these sit under state planning law, assessed at DA/CDC stage)
Builder licensing (state licensing acts, not the NCC)
WHS obligations on site (WHS Act, running in parallel)
Electrical wiring (AS/NZS 3000 Wiring Rules, licensed electrician’s reference)
Gas appliance installation (state-specific energy safety regulations apply beyond the PCA pipe connections)

Practical implications

How this affects your inspection regime

On a Class 1a house, the Principal Certifying Authority (PCA) runs mandatory inspections at prescribed stages. The building inspections check BCA compliance (footing, slab, framing, wet area, final). Separately, licensed plumbers issue Certificates of Compliance for plumbing work, certifying against Volume Three. Both sets of sign-offs are required before an Occupation Certificate (OC) can issue (verified 2026-05-09: NSW EPA, Certificates for residential building work).

If either is missing, the OC stalls. Track both streams independently on your build programme.

Which volume do you actually read?

For most residential builders running Class 1 work:

Volume Two is the daily reference for building compliance obligations.
ABCB Housing Provisions Standard 2022 is read alongside Volume Two: it holds the DTS numbers (footing tables, bracing schedules, fire separation specs). Free download from the ABCB site.
Volume Three is your licensed plumber’s reference. You may not read it line-by-line, but knowing the structure means you know where to point a dispute.
Volume One is only needed if you have a Class 2 to 9 element (common-wall apartment, caretaker’s flat, short-stay complex).

NCC 2025 edition note

NCC 2025 was released 1 May 2026. State adoption is staggered: ACT, Tasmania, Victoria, and Western Australia adopted NCC 2025 at release; NSW and Queensland are scheduled for 1 May 2027; South Australia adopted Volume Three only. Until your state adopts, NCC 2022 remains operative (verified 2026-05-09: NCC 2025 adoption information).

State variations

VIC

The Victorian Building Authority (VBA) regulates both building practitioner registration and plumbing licensing, but the workflows are split. Building permits for Class 1 and 10 work are issued by a private or municipal building surveyor under the Building Act 1993 before any work starts. Plumbing work runs in parallel: the licensed plumber lodges and issues a Compliance Certificate via VBA360 for prescribed work or any job over $750 (incl. GST), and below-ground sanitary drains, gas appliance installations and consumer gas piping always require one regardless of value. The certificate must be issued within five business days of completion and is your evidence of PCA compliance for occupancy and warranty (verified 2026-05-09).

QLD

The Queensland Building and Construction Commission (QBCC) licenses both builders and plumbers/drainers, and administers the Plumbing and Drainage Act 2018. Building work follows the standard development application or accepted-development pathway via the local council or a private building certifier. Plumbing splits three ways by risk: minor work (no notice), notifiable work registered on Form 4 within 10 business days of invoicing (no council permit, no inspection), and compliance assessable work that requires a council plumbing permit and inspection. The plumber issues a Form 4 (or Form 9 for compliance work) as proof of PCA sign-off; a final Form 21 inspection certificate from the council closes out permit work before the building Final Inspection Certificate can issue (verified 2026-05-09).

WA

Building and Energy (within DEMIRS) is now the technical regulator for both building and plumbing, with the Plumbers Licensing Board continuing to administer plumber licensing. Building permits are issued by a permit authority (local government) on application by a registered building surveyor, supported by a BA17 Certificate of Construction Compliance for certified applications. Plumbing work is lodged through eNotice: the contractor files a Notice of Intention before starting major work, then a Certificate of Compliance within five working days of completion under the Plumbers Licensing and Plumbing Standards Regulations 2000. The plumbing notice trail is independent of the building permit but both must be complete before occupancy (verified 2026-05-09).

SA

South Australia splits the regulators: building consent and Development Approval are issued under the Planning, Development and Infrastructure Act 2016 via the PlanSA portal and assessed by an accredited building certifier or council, while Consumer and Business Services (CBS) licenses plumbers, gas fitters and electricians under the Plumbers, Gas Fitters and Electricians Act 1995. Gas trades sit under the Office of the Technical Regulator (OTR), which requires an electronic Certificate of Compliance (eCoC) for every gas installation under the Gas Act 1997. Water and sewerage work connects through SA Water; the licensed plumber’s compliance record sits with CBS while the gas eCoC sits with OTR, so the paper trail is two-stream (verified 2026-05-09).

TAS

Consumer, Building and Occupational Services (CBOS) regulates both building and plumbing under the Building Act 2016, with the Director of Building Control issuing the Determinations that classify work into four risk categories. Building work is split into Low Risk (no approval), Notifiable (Cat 2), Permit Work (Cat 3) and Permit Work requiring planning (Cat 4); the council Permit Authority issues the Building Permit on a Certificate of Likely Compliance from a licensed building surveyor. Plumbing follows a parallel four-category structure under the Director’s Determination – Categories of Plumbing Work: Cat 3 is notifiable, Cat 4 needs a Plumbing Permit from the council Permit Authority and a Certificate of Likely Compliance before work starts, plus a Certificate of Completion at the end (verified 2026-05-09).

NT

The Northern Territory splits regulators along trade lines: the Building Practitioners Board registers building certifiers, builders and certifying plumbers/drainers, while NT WorkSafe houses the Plumbers and Drainers Licensing Board under the Plumbers and Drainers Licensing Act 1983. Building permits are issued by a private building certifier under the Building Act 1993, with drawings lodged with Building Advisory Services for auditing and filing. Plumbing work requires a certifying plumber and drainer to prepare and submit the drawings; if there’s no other building work on the project, the certifying plumber lodges direct with Building Advisory Services. PowerWater connection approvals run separately for water and sewer, so a stand-alone plumbing job can have three sign-off streams: licensing, certification, utility (verified 2026-05-09).

Source link

NCC 2022 (all volumes, free read-only access): https://ncc.abcb.gov.au/editions/ncc-2022/adopted

NCC 2025: https://ncc.abcb.gov.au/ncc-2025

Free ABCB account required for online access; PDFs also free to download.

References

Australian Building Codes Board, NCC overview. https://ncc.abcb.gov.au/ (verified 2026-05-09).
Australian Building Codes Board, NCC 2022 Volume Two, Building Code of Australia Class 1 and 10 buildings. https://ncc.abcb.gov.au/editions/ncc-2022/adopted/volume-two (verified 2026-05-09).
Australian Building Codes Board, NCC 2022 Volume Three, Plumbing Code of Australia. https://ncc.abcb.gov.au/editions/ncc-2022/adopted/volume-three (verified 2026-05-09).
NSW Planning and Environment, Certificates for residential building work. https://www.planning.nsw.gov.au/policy-and-legislation/housing/certificates (verified 2026-05-09).
Australian Building Codes Board, NCC 2025 state and territory adoption information. https://ncc.abcb.gov.au/ncc-2025/ncc-2025-state-and-territory-adoption-information (verified 2026-05-09).

NCC structure: BCA, PCA, volumes and building classes, comprehensive reference for NCC structure
NCC 2022 Volume Two overview, Section H parts in detail
AS 3500, the plumbing standard referenced by the PCA
Deemed-to-Satisfy (DTS), the default compliance pathway under both codes
Performance Solution, the alternative compliance pathway
ABCB Housing Provisions Standard, where the DTS numbers for Class 1 and 10 live
NCC version transition, NCC 2022 vs NCC 2025 and state adoption timetable