Detached Minor Residential Units (Granny Flats)

Detached Minor Residential Units (Granny Flats)

You can find our info sheet here:  RC-INFO-01 - Detached Minor Residential Units (Granny Flats)

You can find Building Consent guidance here: Small Stand-Alone Dwelling Exemption (Granny Flats)

The Government has changed the rules to make it easier to build to granny flats. This guidance document is specific to the changes that have been made to the RMA through the new National Environmental Standard for Detached Minor Residential Units (NES-DMRU), which came into effect on 15 January 2026. A Detached Minor Residential Unit is also known as a granny flat.

This NES will override some rules in the District Plan, unless the District Plan rules are more lenient.

This is general guidance only. Every property is different. We strongly encourage you to contact our Resource Consents Team for further details or to clarify points.

For more a detailed explanation, please see the information below.

The short answer is that it depends on the zone you are in.

The NES-DMRU applies nationally to residential, rural, mixed-use, and Māori-purpose zones. In Lower Hutt, this translates to:

  • All residential zones, including the Hill Residential Activity Area and Landscape Protection Activity Area
  • All rural zones
  • Community Iwi Activity Area
  • Some Commercial zones

Do I need resource consent?

If you are building a granny flat in the above zones, it may not need resource consent but there are specific requirements to meet. This includes:

  • There must be a principal unit that the granny flat is ancillary to.
  • One granny flat per site and must be 70m2 or less in floor area.
  • Building coverage for the site is no more than 50% in residential zones. For other zones, building coverage must comply with the District Plan.
  • The granny must be set back no less than 2 metres from the principal unit.
  • The granny flat must comply with specific setbacks from boundaries, depending on the zone. In some cases, the District Plan setbacks are more lenient than the new NES. These take precedence over the NES in this case.

The NES overrides some rules in the District Plan for granny flats. For example, our windows to street rule, landscape area rule and height to boundary rules will no longer apply to a compliant granny flat.

It is important to note that regardless of whether the building is a granny flat or not, certain rules in the District Plan will still be applicable. These are the rules relating to permeable surfaces, stormwater detention tanks, minimum floor levels, natural hazards and earthworks, for example. Other rules, such as for acoustic treatment near a State Highway or railway will still be applicable. A member of the Resource Consents Team can assist with queries about what rules apply to your property for granny flats. Regional Council’s rules, such as for septic tanks on rural sections, will still apply.

What if my granny flat doesn’t meet these requirements?

The rules of the District Plan must be checked to see if resource consent is required.

The NES overrides some rules in the District Plan for granny flats. For example, our windows to street rule, landscape area rule and height to boundary rules will no longer apply to a compliant granny flat.

It is important to note that regardless of whether the building is a granny flat or not, certain rules in the District Plan will still be applicable. These are the rules relating to permeable surfaces, stormwater detention tanks, minimum floor levels, natural hazards and earthworks, for example. Other rules, such as for acoustic treatment near a State Highway or railway will still be applicable. A member of the Resource Consents Team can assist with queries about what rules apply to your property for granny flats. Regional Council’s rules, such as for septic tanks on rural sections, will still apply.

Does it have to be for residential use?

Yes. If it is not for residential use, the District Plan rules apply rather than the NES.

Does my granny flat have to comply with the height rules for the zone?

If the proposal is deemed to be a granny flat under regulation 6 of the NES, it does not have to comply with height rule of the relevant zone. The only limitation in building size is floor area (being a maximum of 70 m2) and building coverage in the particular zone. However, this is to be read in conjunction with the requirements for granny flats under the Building Act, where building a granny flat that is more than one storey in height will require building consent.

What about recession planes / height to boundary rules?

These rules do not apply to granny flats that meet Regulation 6 of the NES. But if the building does not comply with the NES, then it defaults to the District Plan rules which may include rules around recession planes /height to boundary rules that must be met to not require resource consent.

How many houses can I now construct on my property?

The NES permits one granny flat per site, providing there is one principal unit. For some properties this may result in three dwellings and one granny flat as a permitted activity subject to compliance with the relevant rules in both the District Plan and the NES.

Does this mean I don’t need building consent?

The requirements for building consent have changed in December 2025. Our Building Team can help and you can review here for more information https://www.building.govt.nz/assets/Uploads/projects-and-consents/granny-flats-exemption/granny-flats-exemption-guidance.pdf.

How will development contributions be charged if resource consent or building consent isn’t required?

If applicants are seeking to use the new granny flat exemption under the Building Act, they will first have to apply for a Project Information Memorandum (PIM) to HCC.

A development contribution notice will be issued with the PIM and then must be paid within 20 working days of the building work being completed. Owners will have two years to complete works.

If it complies with the NES and any relevant District Plan rules, it does not need resource consent and there is no avenue to object.

If consent is required, an assessment on neighbours will be undertaken by Council.

Contact us before you get started

You can find the NES here: https://www.legislation.govt.nz/regulation/public/2025/0315/latest/whole.html#LMS1556242

Please contact the Resource Consents Team and the Building Consent Team at Hutt City Council if you have any questions.