From 15 January 2026, two major regulatory changes will take effect that together reshape how detached minor residential units (commonly known as “granny flats”) are delivered in New Zealand:
- Resource Management (National Environmental Standards for Detached Minor Residential Units) Regulations 2025 (NES-DMRU) under the Resource Management Act 1991 (RMA); and
- Changes to the Building Act 2004 introducing a building consent exemption for small standalone dwellings (under the Building and Construction (Small Stand-alone Dwellings) Amendment Act 2025).
These reforms collectively aim to cut red tape, increase affordable housing options and provide consistent national rules. They also create nationwide consistency and significantly lower the consenting threshold for many small dwellings.
What the NES-DMRU does
The NES-DMRU establishes permitted activity standards across New Zealand for detached minor residential units equal to or less than 70 m². If the NES-DMRU conditions are met (including size, setbacks and other standards), these units do not require a resource consent under the RMA in residential, rural, mixed-use and Māori-purpose zones.
The standards are minimum national requirements. Councils retain the ability to regulate minor residential units through their district plans provided plan provisions either align with or are no more restrictive than the NES.
In effect, a qualifying minor residential unit that complies with the NES-DMRU standards does not require a resource consent under the RMA, even if a district plan rule would otherwise trigger consent.
Building consent exemption
In parallel, the government has passed the Building and Construction (Small Stand-alone Dwellings) Amendment Act 2025 that removes the requirement for a building consent for certain small standalone dwellings up to 70 m², subject to conditions such as the design is simple and complies with the Building Code; the work is carried out or supervised by licensed building professionals; and the homeowner notifies the council before the work starts and upon completion.
The building consent exemption introduces a new PIM process specific to these developments. To rely on the exemption, an owner must obtain a PIM before any building work begins and the PIM must confirm whether the site is subject to natural hazards, or whether the proposed work could accelerate or worsen hazard risk. The owner then has two years to complete the build.
What stays regulated
Despite the exemptions matters such as natural hazard risk, heritage values and significant environmental features under the RMA continue to apply and may still trigger separate requirements. Regional plan or resource consent requirements (for example, for wastewater or stormwater) may still be relevant, as well as land covenants and other private restrictions of what can be built on a property.
Implications for councils
For council planners and decision-makers, the NES-DMRU and Building Act exemptions require careful integration into day-to-day consenting and planning functions.
Importantly, compliance with one regime does not automatically mean compliance with the other. A unit might meet the NES-DMRU for resource consent exemption but still need to satisfy Building Act conditions (or vice versa).
For planning and consenting functions, councils should:
- update internal guidance to reflect the NES-DMRU permitted requirements and the Building Act exemption pathways;
- review district plan provisions on minor residential units to ensure they are consistent with or not more restrictive than the NES-DMRU where possible;
- ensure consent checklists and applicant information clearly distinguish between resource consent requirements and building consent exemption criteria to avoid confusion; and
- update consent pathways and internal training for planners, building officers and compliance teams.
How we can help
Rice Speir assists councils to navigate the interaction between the RMA, NES instruments and building regulatory frameworks. We can support councils with interpreting the NES-DMRU and Building Act exemptions, advising on plan alignment, conditions and implementation as well as updating practice notes, consent processes and training materials.
If you’d like advice on how these changes affect your district or region, please get in touch.
