35. Alteration to existing sanitary plumbing (excluding water heaters)

Plumbing work under a bathroom sink

A building consent is usually not required to alter existing sanitary plumbing in a building, if it is carried out by an authorised person. 

What the law says

Schedule 1 of the Building Act 2004 states the following:

1. Alteration to existing sanitary plumbing in a building, provided that:

(a) the total number of sanitary fixtures in the building is not increased by the alteration; and
(b) the alteration does not modify or affect any specified system.

2. Subclause (1) does not include an alteration to a water heater.

Guidance on the exemption

This exemption enables an authorised person (refer to the glossary) to carry out alterations to sanitary plumbing. However, this is only as long as these alterations do not increase the number of sanitary fixtures within any existing building and they do not modify or affect any specified system.

Check with your council

If you are not sure if this exemption applies to your proposed building work, we recommend that either you seek an exemption 2 from the council or you apply for a building consent rather than risk applying it incorrectly.

Alterations to water heaters are specifically excluded from this exemption. However, there is still some building work in relation to water heaters which does not require a building consent: this is covered in the next three exemptions (exemptions 36, 37 and 38).

Any plumbing work under this exemption must be carried out by an authorised person, otherwise it is not exempt work.

Plumbing work that could affect structural elements

Where sanitary plumbing work could adversely affect the structural performance of structural elements such as floor joists or wall framing, this work may require a building consent. If you are not sure, we recommend seeking professional advice first (eg from a licensed building practitioner, chartered professional engineer, registered architect, building consultant, registered building surveyor or accredited building consent authority).

Examples where this exemption could apply

Repositioning or replacing sanitary fixtures (eg a bath, bidet, wash hand basin, shower or toilet pan) within an existing bathroom in a dwelling.
Moving a toilet pan from a toilet compartment into an adjacent existing bathroom in a dwelling.
A home owner proposes to remodel an existing kitchen within the same space, leaving the kitchen sink in the same position.
An existing laundry tub in a dwelling will be moved to a new location within the adjacent kitchen.
Relocating, removing or shifting an existing hose tap.
Removing a bath with a shower over it, and replacing this with a new proprietary shower enclosure and a new bath within the existing bathroom space. As the existing bath/shower arrangement has two sanitary fixtures, each fixture can be replaced and relocated without the need for a building consent.
Installing a tiled wet area shower will require a building consent. This is because it will involve critical building work that is not sanitary plumbing, such as carpentry and installing waterproof membranes.
Moving a vanity, bath and shower within an apartment of a multi-level building. This building work involves new penetrations through a fire separation, which is a specified system.
An ensuite is proposed which includes the addition of a shower, hand basin and toilet. These sanitary fixtures are additional to those that already exist in the building, so a building consent is required.
A restaurant owner decides to increase the number of sanitary fixtures to allow for increased customer capacity. This building work will require a building consent.
Installing a new testable backflow prevention device in a building (that is not a dwelling). As this device is a specified system, a building consent is required and the compliance schedule will also need to be amended.

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: