NCC 2019 Volume Three
Part C1 Sanitary plumbing systems

Part C1 Sanitary plumbing systems

Introduction to this Part

This Part sets out the requirements for the design, construction, installation, replacement, repair, alteration and maintenance of any part of a sanitary plumbing system of a property including from sanitary fixtures and appliances to an approved disposal system.

Explanatory information:

Explanatory information:



The Objective of this Part is to—

  1. safeguard people from illness, injury or loss (including loss of amenity) due to the failure of a sanitary plumbing installation; and
  2. ensure that a sanitary installation is suitable; and
  3. conserve water and energy; and
  4. safeguard the environment; and
  5. safeguard public and private infrastructure; and
  6. ensure that a sanitary installation is designed and is capable of being maintained so that throughout its serviceable life it will continue to satisfy Objectives (a) to (e).



Sanitary fixtures and sanitary appliances must be provided with an adequate disposal system that does not impact adversely on occupants of the premises, property, the environment or the Network Utility Operator's infrastructure.

Performance Requirements

CP1.1 Design, construction and installation


A sanitary plumbing system must ensure the following:


Sewage or sullage is transferred to a sanitary drainage system or an approved disposal system.


Access for maintenance of mechanical components, operational controls and for clearing blockages.


Ventilation, to avoid hydraulic load imbalance is provided.


Effective and efficient water use.


A sanitary plumbing system must avoid the following:


Entry of water, sewage, sullage, foul air and gases from the system into buildings.


Damage from superimposed loads, ground movement or root penetration.


Entry of surface water, subsurface water and stormwater into the system.

Explanatory information: Non-flushing (waterless) urinals

Explanatory information: Non-flushing (waterless) urinals

Where a non-flushing (waterless) urinal is to be installed to a sanitary plumbing system comprising copper, copper alloy or other metallic piping, undiluted discharge transported through such pipework may increase the likelihood of corrosion.

Practitioners should also be aware that undiluted discharge, transported through pipework of any material, can cause a build-up of struvite (ammonium magnesium phosphate) inside the pipework, potentially causing blockage within the sanitary plumbing system.

Verification Methods

There are no Verification Methods in this Part.

Deemed-to-Satisfy Provisions

C1.1 Application


Performance RequirementCP1.1 is satisfied by complying with C1.2 and C1.3.

C1.2 Invert levels


The invert level of a trap or gully weir must be a minimum of 10 mm higher than the soffit of the pipe to which it connects.

C1.3 General requirements

NSW C1.3(1)

SA C1.3(1)

Vic C1.3(1)


The design, construction, installation, replacement, repair, alteration and maintenance of a sanitary plumbing system must be in accordance with AS/NZS 3500.2.

Explanatory information: Cross-volume considerations

Explanatory information: Cross-volume considerations
NCC Volumes One and Two deal with a number of areas of on-site construction which are relevant to sanitary plumbing services. These include, but may not be limited to, the following:


NCC Volume One Class 2 to 9 buildings

NCC Volume Two Class 1 and 10 buildings

Termite management for attachments to buildings and penetrations through a slab

B1 Structural provisions

3.1.4 Termite Risk management

Penetrations for pipework through a vapour barrier

B1 Structural provisions

3.2.2 Preparation

Pipework in timber bearers and joists of solid timber or engineered wood products

B1 Structural provisions

3.4.0 Framing

Fittings, fixtures and pipework installations in steel framed construction

B1 Structural provisions

3.4.2 Steel framing

Penetrations through a fire-resisting wall or floor

C3 Protection of openings

3.7.3 Fire protection of separating walls and floors

Fixtures or fittings in a wet area

F1 Damp and weather proofing

3.8.1 Wet areas and external weatherproofing

Service pipework external to the building and penetrations through roof cladding in a bushfire prone area

G5 Construction in bushfire prone areas

3.10.5 Construction in bushfire prone areas

Pipework sound insulation

F5 Sound transmission and insulation

3.8.6 Sound insulation

Tas Part C101