Granny flat rules in Porirua.
A small home in Porirua may provide accommodation for whānau, other family members or tenants. Established suburbs such as Titahi Bay, Cannons Creek and Ranui have different site conditions from newer northern subdivisions. Hill properties need slope, retaining and access considered. Harbour-edge and stream-adjacent land needs hazard information, while some newer estates have covenants. The design also needs wind specifications and services appropriate to the actual property.
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 applicable planning and title requirements, including covenants in newer northern subdivisions. Hill sites need slope, stability, retaining and construction access considered. Harbour-edge and stream-adjacent properties may have flood or siting requirements. Ground conditions, wind and services also need to inform the proposed design.
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
Slope and ground conditions determine foundation and retaining requirements. Wind exposure needs to be established for the property. The indicative construction period for flat sites is 10 to 12 weeks; hill sites may take longer because of access and additional work.
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 an established Porirua section accommodate a 70 m² home?+
It may be possible where there is enough space, practical access and suitable services. A large section still needs to meet applicable planning and title requirements. Where a property has multiple owners or trustees, the necessary decisions and approvals also need to be established.
What affects site suitability in Porirua?+
Slope, stability, retaining and access affect hill properties, while harbour-edge and stream-adjacent sites may have water-related constraints. Wind and services also matter. Conditions vary between streets and properties, so suitability needs to be established for the specific proposed dwelling.
What should I use to estimate rent in Porirua?+
Use current listings for comparable homes near the property, taking account of condition, access to rail and local services. Potential tenants include commuters, health staff and families. Include vacancy and ongoing expenses rather than treating an advertised rent as a guaranteed return.
Any water-side checks around the harbour?+
Harbour-edge and stream-adjacent properties may have flood, inundation or siting requirements. Check the current information for the address rather than assuming an established section is unaffected. The design needs suitable floor levels, drainage and foundations for its actual conditions.
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 Wellington · Wairarapa
Regional guidance and nearby council guides.