Resource management regulations for detached minor units (granny flats)

Recent government changes make it easier for homeowners to build self-contained detached minor residential units (DMRU) on their existing properties. You can now build a DMRU up to 70m2 without a building consent, as long as it meets all exemption criteria.

We strongly recommend checking all requirements before starting any work.

What you need to do before starting work

Notify Council before and after construction. You can do this here.
Make sure the build fully complies with the Building Code.
Check the Building Guidance resources.
Read and understand the relevant legislation.
Check what other approvals you may need.

Please note: A building consent exemption does not override other requirements, such as:

resource consent (if needed under the Resource Management Act 1991).
approvals for utilities, vehicle crossings, or land‑use constraints.
development contributions.
network connection approvals.

National Environmental Standards (NES) for DMRUs

To qualify as a permitted activity under the NES, a DMRU must meet all of the following requirements:

One DMRU per site.
Maximum internal floor area of 70m2.
Must be set back 2m from the main dwelling.
In residential zones: a maximum of 50% building coverage for all buildings on the property.
In residential zones: must be set back at least 2m from the front, side, and rear boundaries.
In rural zones: must be set back at least 10m from the front boundary and 5m from the side and rear boundaries.

If the detached DMRU you are proposing does not meet the permitted activity standards, then the rules in the Hamilton City Council District Plan apply.

District Plan rules that still apply

Some Council rules apply to all DMRUs, even if they are exempt from building consent requirements. These rules include:

subdividing land
protecting natural or cultural sites
non-residential uses
papakaainga (communal Maaori housing)
earthworks
any health and safety requirements that also apply to the main house – such as managing natural hazards, setbacks (distance from) from utilities or industrial sites, new vehicle crossings
infrastructure requirements.

All relevant regional plan rules still apply.

Frequently Asked Questions

What if my property is in a wastewater capacity constrained area?

Yes, you can build a DMRU if you can connect it to the existing wastewater connection for the main dwelling, and if all other building and resource consent exemption criteria are met. Check out the wastewater capacity map here.

Do I need a resource consent if I do not need a building consent?

Possibly. Even if your DMRU meets the building consent exemption criteria, you may still need a resource consent depending on site constraints such as: