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Detached Minor Residential Units (DMRUs)

New Government rules for detached minor residential units (effective 15 January 2026)

The Government has introduced new rules that enable homeowners to build detached minor residential units (DMRUs) - often referred to as ‘granny flats’ - of up to 70 m² without the need for resource consent, provided specified requirements are met. As of 15 January 2026, changes to both the Building Act 2004 and the Resource Management Act 1991 (RMA) are now aligned to simplify how these units can be built.

What’s changing?

 The government has introduced a dual‑exemption approach:

Building Act – Exemption from building consent

Under the Stand‑alone Dwellings Amendment Bill, certain small dwellings will no longer require a building consent, provided they meet the criteria for safety and structural compliance and a Project Information Memorandum has been applied for. All building work must comply with the New Zealand Building Code and must be carried out or supervised by licensed building professionals.

Resource Management Act – NES–DMRU 2025

The new National Environmental Standards for Detached Minor Residential Units remove the need for a resource consent when the unit meets the prescribed standards for where it can be located.

These changes work together to make building a compliant granny flat faster and more straightforward.

  • A DMRU is a small, fully detached, self-contained residential unit up to 70m².  

    They have to meet all of the regulations outlined in:

    1.  Schedule 1A Section 2 of the Building Act 2004

    2. National Environmental Standards for Detached Minor Residential Units Regulations 2025 of the Resource Management Act 1991.

  • Because the rules are not always straightforward, we encourage you to seek professional planning advice.  A qualified planner can help you understand:

    ·       whether your proposal qualifies as a DMRU

    ·       whether your site is affected by District Plan overlays or other constraints

    ·       whether your proposal is permitted or requires resource consent

    ·       what information you’ll need before you start building

    Getting advice early can save you time, cost, and redesign later.

    There are also some restrictions on how DMRUs can be used so it’s important to seek good professional planning advice to ensure it will meet your requirements. 

  • As with any building project, you may require a resource consent, a building consent, or neither depending on your plans. Before you begin, you should talk your plans through with a professional planner, who can advise whether a DMRU is the best option for your circumstances. Even if your proposal meets all DMRU standards, your site may still require a resource and/or building consent.

  • A Project Information Memorandum (PIM) must be applied for and issued before any building work starts. A PIM gives you a clearer picture of the planning and building requirements before you commit to design or construction.

    Your PIM application must include:

    ·       preliminary design plans

    ·       a description of the proposed building work

    Before applying, ensure you have:

    ·       met all exemption criteria using the Building design conditions checklist

    ·       completed the Homeowner due diligence checklist

    How to apply and more information

    More information on how to apply and the costs and timeframes involved can be found on our Other Building Services page. 

  • Please visit our Other Building Services page for the full requirements, including what needs to be done once building work is complete. This guidance explains the approvals, documentation, and steps you must follow during and after construction.

This practice note explains the key requirements and common issues to be aware of when planning or building a granny flat (DMRU). It provides practical guidance to help planning professionals, homeowners and builders understand what is expected, how to meet the relevant standards, and should be read alongside the information on this page.