Plumbing and drainage work exempt from a consent when carried out by an authorised person

Last updated: 15 March 2016

If you are undertaking plumbing and drainage work, you may not need a building consent if an authorised person completes the work.

You must employ an authorised person to carry out building work listed in Part 2 of the Building Act's Schedule 1 in order for it to be exempt from needing a building consent. If an authorised person does not complete the work, then it is not exempt.

Work in Part 2 relates to sanitary plumbing and drainlaying.

The term ‘authorised person’ is defined by the Building Act. For building work in Part 2, it covers:

  • registered certifying plumbers and drainlayers
  • registered plumbers and drainlayers working under supervision
  • plumbers and drainlayers with a provisional licence working under supervision
  • trainee plumbers and drainlayers working under supervision. must make sure the plumber or drainlayer you are using for your building work has current authorisation from the Plumbers, Gasfitters, and Drainlayers Board.

Plumbers, gasfitters and drainlayers register

You must make sure the plumber or drainlayer you are using for your building work has current authorisation.

Check the online register

Exemptions under Part 2

Part 2 has seven exemptions divided into two broad categories:

  • plumbing and drainage
  • water heaters.

You can find specific and technical details about each exemption in MBIE's Schedule 1 Guidance: Building work that does not require a building consent document.

What the exempt work includes

Plumbing and drainage

1. Repair, maintenance and replacement

This exemption enables a range of work relating to repair, maintenance and replacement of sanitary plumbing or drainage to be done without a building consent – as long as it is carried out by an authorised person.

For repairs and maintenance, comparable materials must be used.

For replacement work, comparable components or assemblies can be used providing replacement is in the same position.

2. Drainage access points

This exemption covers work to drains via a purpose-made access point and carried out by an authorised person.

3. Minor alteration to drains

This exemption only relates to houses and enables an authorised person to alter existing private drainage.

This sort of building work usually occurs during alterations to existing bathrooms, kitchens, laundries or toilets.

New connections to public drainage are excluded from this exemption.

4. Alteration to existing sanitary plumbing

This exemption enables an authorised person to carry out alterations to sanitary plumbing, as long as the alterations do not increase the number of sanitary fixtures within the existing building and do not modify or affect any specified system.

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 if this exemption applies to your proposed building work, you should either:

  • seek an exemption 2 from your local council
  • apply for a building consent.

You should seek professional advice to determine whether the work will affect the structure of the building. This can include talking with:

  • a licensed building practitioner
  • a chartered professional engineer
  • a registered architect
  • a building consultant
  • a registered building surveyor
  • an accredited building consent authority.

Alterations to water heaters are specifically excluded from this exemption. However, building work related to water heaters that do not require a building consent is covered below.

Water heaters

You will need to apply to your council for an Exemption 2 if the proposed scope of the building work is outside the scope of the exemptions below.

For example, adding solar collectors to an existing water storage heater which has provision for solar connection and is not being replaced or repositioned.

Building consent exemptions for low-risk work

An overview of building work that usually doesn't require a building consent.

Applying for an Exemption 2

5. Repair and maintenance of existing water heater

This exemption enables an authorised person to repair and maintain water heaters associated with buildings using either:

  • comparable materials
  • comparable components
  • a comparable assembly.

6. Replacement of open-vented water storage heater connected to supplementary heat exchanger

An authorised person must replace open-vented water storage heaters associated with existing supplementary heat exchangers (such as wetbacks or solar collection panels).

The replacement of any water-storage heater connected to a solid-fuel heater or other supplementary heat exchanger if the replacement:

  • is a comparable open-vented water storage heater
  • is fixed in the same position
  • and uses the same pipework as the replaced water storage heater.

The replacement water storage heater must be comparable and in the same position.

7. Replacement or repositioning of water heater that is connected to, or incorporates, controlled heat source

An authorised person must replace or reposition an existing water heater (of any type), as long as all the heat sources of the replaced or repositioned water heater are controlled.

This exemption includes the replacement of any water heater (including the repositioning of an existing water heater) if the replacement water heater is:

  • connected to or incorporates a controlled heat source
  • or if connected to or incorporating more than 1 heat source, 2 or more heat sources all of which are controlled.

This exemption will not apply if a water heater has a heat source that is not controlled (such as a wetback connected to a solid-fuel heating appliance, or a solar thermosiphon system). A controlled heat source has controls or devices that ensure the water temperature in the storage tank is no greater than 90°C.

Council maps and websites

Your local council can tell you about the requirements and exemptions related to your district.

Find your local council

If you are unsure about whether your building work is exempt from a building consent, you should refer to the Schedule 1 Guidance: Building work that does not require a building consent document above.

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: