Granny flat rules in Buller.
A small home in Buller may suit family members or people working in mining, port operations, services and health. Flood conditions are a key consideration for properties in and around Westport, particularly following the 2021 floods. Reefton also has heritage requirements in some streets. The design needs to suit heavy rainfall, the site's ground conditions and any coastal exposure. Property suitability and the full construction cost need to be assessed before choosing a design.
Building consent and resource consent requirements
The building consent exemption and the national planning standard are separate. A project can proceed without either consent only when all the relevant requirements are met.
Schedule 1A, under the Building Act 2004
Building consent, if all Schedule 1A conditions are met
A new, detached, single-storey home up to 70 m² may be built without a building consent if every exemption condition is met. Licensed professionals, Building Code compliance, a Project Information Memorandum and council notifications are still required.
NES-DMRU, under the Resource Management Act 1991
Resource consent, if all relevant requirements are met
The national planning standard can permit one detached minor dwelling without resource consent when its standards and other relevant requirements are met. Some district and regional rules remain, including those for hazards, infrastructure and earthworks.
Both took effect on 15 January 2026. They do not retrospectively approve existing dwellings.
National planning standards
The NES-DMRU is the national planning standard for detached minor dwellings. These measurements apply when its requirements are met. A district plan can allow more generous measurements. Other relevant site restrictions still apply.
| Standard | Residential zone | Rural zone |
|---|---|---|
| Maximum internal floor areaMeasured to the internal face of the external walls. An attached or internally accessed garage counts inside it. | 70 m² | 70 m² |
| Maximum area of the site covered by buildingsThe 50% standard overrides any district plan coverage standard below 50% in a residential zone. | 50% | As required by the zone |
| Minimum distance from the main homeDistances are measured from the outside face of the wall cladding. | 2 m | 2 m |
| Minimum distance from the front boundary | 2 m | 10 m |
| Minimum distance from side and rear boundaries | 2 m | 5 m |
The permitted activity rule: One detached minor residential unit per site. It applies in residential, rural, mixed use and Māori purpose zones, as defined in the National Planning Standards, or the equivalent zones where a council has not implemented them yet.
- Special character, design guides and visual amenity
- Screening for rubbish and recycling storage
- Wall and roof colour, reflectivity and external finishes
- Minimum outdoor open space, privacy or sunlight access
- Minimum window area
- Parking
- Minimum site size
- A design that satisfies a local character guide
- A minimum private outdoor space around the unit
- A sunlight or privacy assessment for the neighbours
- An on-site car park
- A minimum site area under the district plan
- Neighbour notification for a permitted activity
Other requirements for your property
Check current flood mapping around Westport and the Buller floodplain, including any relevant resilience or managed-retreat planning. These may affect whether and where a dwelling can be built. Coastal properties need erosion and salt-exposure information. Reefton properties may also have heritage or character requirements.
Flooding, coastal hazards, fault lines and land stability can affect the building location, floor level and need for consent. Check the council information and obtain site advice where needed.
Check connection requirements and capacity. Relevant regional plan rules still apply, including requirements for an on-site wastewater system.
Buildings near electricity lines and other significant infrastructure must meet the relevant safe-distance and planning requirements.
Rules can apply near airports, ports, industry and farming operations, or on contaminated land. They may affect where a home can be built and what design measures are needed.
Earthworks may need resource consent even when the dwelling does not. Subdivision requirements are separate and remain in place.
Relevant protections for heritage, cultural sites and outstanding natural features still apply.
Check covenants and easements on your property title. The national planning standard does not override private covenants, and more stringent council bylaws can still apply.
Development and financial contributions may be payable. Ask your council to confirm which charges apply to your project.
A district plan may allow a larger home or a smaller boundary setback. That does not change the separate Schedule 1A requirements. For example, an 80 m² dwelling or a 1 m setback would not meet the 70 m² and 2 m conditions for this building consent exemption.
Check the main eligibility conditions
Check these conditions with your designer and council. They are a starting point; all relevant exemption requirements must be met.
The minor dwelling must be physically separate from the principal home. An attached extension is assessed under different requirements.
The NES-DMRU planning standard requires a minor dwelling to be secondary to a principal home on the same site and in the same ownership. If both are proposed together, confirm the construction order and requirements with the council.
The NES-DMRU allows one detached minor dwelling per site. For a cross-lease, the site includes all the land under the cross-lease. A district plan may allow more, subject to its requirements.
The building consent exemption applies to new dwellings. A building conversion may meet the planning standard, but it is not covered by this building consent exemption.
Ground, climate and construction
Drainage, cladding and flashings need to suit rainfall that can reach two metres annually. Foundations depend on the ground report for river silts or coastal sands. The indicative construction period is 11 to 13 weeks, subject to freight, access and weather.
Steps to plan your project
Review the title, planning requirements and services with your designer, builder and council before construction.
Check covenants and easements that could restrict a second home, its size, location or access.
Review council maps and relevant district and regional rules for natural hazards, infrastructure and other restrictions.
Identify the water, wastewater and stormwater connections and confirm capacity. Check any requirements for an on-site wastewater system.
Apply for and receive a Project Information Memorandum before construction starts. It records the council information relevant to the property and proposed work.
Your designer confirms the design requirements for the property and prepares the required plans and documentation. The Schedule 1A exemption requires appropriately licensed professionals.
Notify the council before construction and provide the required completion documents afterwards. Your designer and builder must supply the records and certificates required for their work.
Frequently asked questions
Can I build a small home in Westport after the floods?+
It depends on the specific property and current flood information. Some sites may accommodate a dwelling with appropriate floor levels or siting, while others may be unsuitable. Relevant flood, resilience and planning requirements need to be reflected in the design.
What should I consider for a small home in Reefton?+
An established section may have space for family or rental accommodation. Check access, services and ground conditions, as well as heritage or character requirements that may affect visibility and materials. Any rental estimate should use current local demand and allow for vacancy.
How does Coast rain change the build?+
High rainfall affects gutters, downpipes, ground drainage, cladding and flashings. Those elements need to be designed for the property's conditions and built as specified. Your builder also needs to allow for wet weather when arranging construction and deliveries.
Who might rent a small home in Buller?+
Potential tenants include mining, port, services and health workers. Demand differs between Westport, Reefton and smaller communities. Check current rents and available housing for the location, and include vacancy and ongoing costs when estimating the return from a rental home.
Official guidance
Use the official guidance below and confirm current district requirements with your council before construction.
- NES-DMRU: Frequently Asked QuestionsMinistry for Cities, Environment, Regions and Transport, September 2026 (INFO 1387)
- National Environmental Standards for Detached Minor Residential UnitsMinistry for the Environment
- Granny flats exemption guidance and resourcesBuilding Performance, MBIE
- Changes to allow granny flats to be built without a building consentBuilding Performance, MBIE
Checked against these sources in September 2026. Confirm the current requirements for your property before construction.
More information for West Coast
Regional guidance and nearby council guides.