G12 Water supplies

Requires the safe supply, storage, reticulation and delivery of hot and cold water.

This clause requires buildings provided with water outlets, sanitary fixtures or sanitary appliances to have safe and adequate water supplies (including where hot water is necessary). It sets out requirements to avoid scalding, injury, leaks, contamination, illness and the prevention of legionella growth.

For example, water for human consumption, food preparation, utensil washing or oral hygiene must be potable and protected from contamination. Where a non-potable water supply system is installed for personal hygiene, it must be installed to avoid illness or injury and be clearly identified.

Record of amendments is a record of changes to the acceptable solutions, verification methods and handbooks.

Lead in plumbing products

In November 2022, MBIE announced changes coming to Acceptable Solution G12/AS1 to limit the maximum allowable content of lead permitted in plumbing products. The amended document will limit the maximum lead content of any product that contains copper alloys, intended for use in contact with potable water for human consumption. This includes products such as pipe fittings, valves, taps, mixers, water heaters, and water meters. The transition period for this change will end on 1 September 2025.

More information about the new requirements for lead in plumbing products for G12/AS1

Building Code Regulations

The Building Code is published in Schedule 1 of the Building Regulations 1992.

The Building Code clauses include objectives, functional requirements and performance criteria. These are mandatory provisions that all new building work must comply with.

The acceptable solutions and verification methods provided on this page are deemed to comply with Building Code clause G12.

Clause G12 — Water supplies


Acceptable Solutions and Verification Methods

Current version

MBIE has historical versions of the code clause documents which can be located under 'Previous Versions' and 'Version History'. Alternatively if you cannot find the document you are looking for, you can send an email with the year and code clause you are after to info@building.govt.nz.


Acceptable Solutions and Verification Methods (AS and VMs) were called compliance documents. Some still have the “compliance document” title but the AS or VMs they contain are valid and unaffected by the name change.


Standards are frequently referred to in Acceptable Solutions and Verification Methods. They provide practical information and guidelines for building solutions.

Over 120 building standards used for Building Code compliance are now available for free download.

See the free standards relating to Code Clause G12.

All standards, including the funded ones, can be accessed through the Standards New Zealand website.


These documents are provided for assistance. They are not intended as a means of establishing compliance with the Building Act or Building Code, and they do not have the same status accorded to Acceptable Solutions and Verification Methods under the Act.

Related Determinations

Determinations are made by MBIE on matters of doubt or dispute to do with building work. Rulings are legally binding in relation to each case. Circumstances in one case may differ to others.

Related building products

All products, systems and construction methods that have achieved CodeMark status will be listed here with their most up to date certificate.

This information is published by the Ministry of Business, Innovation and Employment’s Chief Executive. It is a general guide only and, if used, does not relieve any person of the obligation to consider any matter to which the information relates according to the circumstances of the particular case. Expert advice may be required in specific circumstances. Where this information relates to assisting people: