Many Hamilton granny flats still need consent, even after the 2026 rules.

It depends. Under Hamilton's District Plan, an ancillary residential unit is a permitted activity if it complies with all the relevant standards (60m² maximum, setbacks, coverage, impervious surface, outdoor living area, three waters capacity). Miss any one of those standards and the activity status drops to restricted discretionary, which means you need resource consent. Most sites either qualify as permitted or land cleanly in restricted discretionary - both are well-worn paths and most applications are approved without notification. We'll tell you within 1 working day which pathway applies to your property.

The 2026 rules introduce a separate national pathway. They let you build up to 70m² without resource consent or building consent in some cases, but every condition has to be met: site size, setbacks, height, wastewater, permeability, outdoor living area. Go over 70m² and you are back in the consent system entirely. Stay under 70m² but miss one condition and the same thing happens. The Hamilton District Plan still applies on top. In practice, only a portion of Hamilton sites actually qualify for the permitted pathway under either rule set - we check both and tell you which is right for your site.

For a standard ancillary unit in Hamilton, budget $8,000 to $12,000 total. That covers council direct-pay fees (a restricted discretionary application is $3,248 at current HCC fees) plus our professional fees for the full application, AEE, and coordination. Simple consents start from $7,000. Multiple infringements or complex sites: $10,000 to $13,000+. We give you a firm quote after the free site assessment, so there are no surprises.

Council has 20 working days to process a non-notified consent once it is accepted. End-to-end (from your call to consent in hand): expect 4 to 8 weeks for a standard granny flat application. The big variable is application quality - a well-prepared application sails through. A sloppy one gets hit with an S92 request, which stops the clock and can add weeks.

If council notices, they issue an abatement notice or stop-work notice. From there, two paths open up: apply for retrospective consent (which costs 50 to 100% more than the original consent process and is not guaranteed to be granted), or demolish the work. If retrospective consent fails, demolition is the usual outcome. Ongoing or wilful non-compliance can also be prosecuted under the Resource Management Act. Beyond enforcement, non-consented work shows up on the LIM report when you sell the property and routinely derails sales, and most home insurance won't cover work that wasn't consented. The path of least pain - by a long way - is getting it right before you build.