Building consent in Auckland: what you need before you build, and what to do if you didn't

I get some version of this question on nearly every listing I take or every sale I make. An owner tells me about the

deck they built last summer, the wall they took out for an open-plan kitchen, or the garage they lined out years ago, and asks, almost as an aside, whether any of it needed council sign-off. Half the time the answer surprises them, in both directions.

The mistake nearly everyone makes is judging consent by how big or expensive a project feels. That's not how the rules work, and there are actually two different rulebooks depending on what kind of project you're doing. For anything you're building from scratch outside, decks, retaining walls, fences, pools, the test is a number: a height, a fall distance, a litre capacity. For anything you're altering inside an existing space, kitchens, bathrooms, garages, the test is different, and it comes down to three questions. Are you touching a structural element? Are you increasing the number of sanitary fixtures in the house? Are you changing what the space is legally used for? Any yes, and you need consent. Everything else is generally just maintenance. Get either test wrong and you find out at the worst possible time, when a buyer's lawyer or your insurer asks for a Code Compliance Certificate you don't have.

Decks

Auckland Council's exemption for decks isn't about how high the deck sits above the ground you're standing on when you build it. It's about fall height, the distance you'd drop if you went through the edge. A deck is unlikely to need a building consent if that fall height stays at or under 1.5 metres, but on a sloped Bays section the fall height and the deck height off the ground can be very different numbers. A deck that reads as a comfortable step up from the lawn on the high side can still have a two or three metre drop on the low side, and it's that low-side number Auckland Council measures against the threshold. Get this checked before you build, not after.

Retaining walls

The rule most people know, a wall 1.5 metres or under is unlikely to need a building consent, is only half of it. The other half is whether the wall carries a surcharge: a driveway, a structure, or a slope sitting above it. A wall well under 1.5 metres that's holding back a driveway, or sitting below another retaining wall, will still need consent, because it's carrying more than its own retained soil. Given how many sections across Mairangi Bay, Murrays Bay and Rothesay Bay are terraced, this is probably the single most common consent trap on the Shore. If the wall sits on or near a boundary, add your neighbour's written agreement to the list too.

Fences and pool barriers

General fences are treated generously; a standard boundary fence up to 2.5 metres is unlikely to need a building consent. Pool barriers are a different regime entirely, and it catches people out because a pool fence looks like an ordinary fence. Any residential pool holding water 400 millimetres deep or more needs a compliant child safety barrier under Building Code clause F9, and that barrier generally needs its own consent regardless of whether the pool itself was exempt. It's also inspected by the council every three years, not signed off once and forgotten.

Swimming pools

Two separate questions here, and owners usually only think about the first one. Does the pool structure itself need consent? A pool resting directly on or in the ground is unlikely to need one as long as capacity stays at or under 35,000 litres, which covers a lot of ordinary in-ground pools (a 7 by 5 metre pool at 1 metre deep sits right at that threshold). Go above 35,000 litres and the structure itself will need consent.

Raised above-ground and portable pools run on a different, height-based scale instead: roughly up to 250mm high holding 16,000 litres, up to 500mm high holding 8,000 litres, up to 1 metre high holding 2,000 litres, or up to 4 metres high holding 500 litres. The second question, the barrier, applies almost regardless of the answer to the first. A portable pool only avoids the barrier rules if it's genuinely emptied and packed away after each use; leave it filled overnight and the same safety requirements apply as a permanent pool.

Bathroom renovations

The trigger here is narrower than most people assume, and more forgiving in one respect. Repositioning or replacing a sanitary fixture, a bath, basin, shower or toilet, within an existing bathroom is unlikely to need a building consent, and that stretches further than same-spot swaps: moving a toilet pan into an adjoining existing bathroom is covered too. It also covers removing a bath with a shower over it and replacing it with a new proprietary shower enclosure plus a new bath, within the same bathroom space. That one trips people up, because it looks like you're going from one wet area to two. You're not. Council counts a bath-with-shower-over as two sanitary fixtures already, so splitting them into a separate shower and a separate bath doesn't increase the total, it just gives each fixture its own footprint. That's the real test running through this whole section: not whether a fixture moved, but whether the total number of sanitary fixtures in the house goes up.

What tips it into consent territory: installing a tiled wet-area shower, because the waterproof membrane and carpentry involved go beyond sanitary plumbing; adding fixtures that genuinely didn't exist before, a new ensuite shower, basin and toilet where there was none; and moving fixtures within a multi-level apartment, where new penetrations can affect fire separation between units. If the plumbing work could affect structural elements like floor joists or wall framing, that pulls it into consent territory too, regardless of which category above it otherwise falls into.

Kitchen renovations

Cosmetic kitchen work, new cabinetry, benchtops, a splashback, is unlikely to need a building consent. The two triggers that generally do are taking out a wall, and moving plumbing or gas. Removing any wall for an open-plan layout needs a structural assessment first, because a wall can be load-bearing, part of the bracing system, or a fire separation element even if it looks like a simple partition, and any of those statuses means consent. Separately, relocating a sink or gas hob to a new position for an island bench is its own consent trigger, independent of whether any wall comes out at all.

Garage conversions

This is the one where people get the logic backwards. A garage conversion doesn't trigger consent because you're changing the structure, plenty of conversions leave every wall exactly where it is. It triggers consent because you're changing the use, from non-habitable space to habitable space, and that pulls in insulation, ventilation, moisture control and fire separation requirements under the Building Code regardless of what you touch physically.

Swap the roller door for a ranch slider on its own, and that's generally fine without consent, it falls under the same exemption that covers replacing any window or exterior door in an existing house, because you're changing an opening, not the building's use. Line the walls, insulate, carpet it and start calling it a bedroom or a home office, and you've crossed into change of use, which needs consent regardless of how tidy the workmanship is.

I'll also flag the workaround I hear suggested most often: calling the finished space a granny flat to use the new consent-free pathway. I've written about why that exemption is rarely as simple as it sounds, and the short version for this context is that it only covers new, detached, single-storey builds up to 70 square metres. A conversion of existing space doesn't qualify under any version of that rule.

Two more things specific to this market. First, the Unitary Plan sets a minimum off-street parking requirement for most sites, and losing your garage can put a property below that minimum, which matters at resale even when the conversion itself is fully consented. Second, if your property is cross lease, which a good share of the Shore's older stock is, and the garage is named on your existing flats plan, you'll need legal advice on updating that flats plan alongside the building consent. It's an extra step owners rarely budget time for.

Building consent in Auckland: quick reference

Project	Unlikely to need consent if	Needs consent if
Deck	Fall height 1.5m or less	Fall height over 1.5m (measure the drop, not the step)
Retaining wall	Under 1.5m, no surcharge above it	Any height with a driveway, structure or slope above it
Fence	Standard boundary fence up to 2.5m	Forms part of a pool barrier
Pool structure	On/in-ground up to 35,000L; above-ground within its own height/capacity tiers	On/in-ground over 35,000L; above-ground beyond those tiers
Pool barrier	Almost never, once water depth reaches 400mm	Always, if the pool holds 400mm or more of water
Bathroom	Fixtures repositioned within the same or an adjoining bathroom; bath swapped for a proprietary shower	New tiled wet-area shower, added fixtures, or work affecting fire separation or structure
Kitchen	Cosmetic only (cabinetry, benchtop, splashback)	Wall removed, or plumbing/gas relocated
Garage conversion	Never, if it becomes habitable space	Always, regardless of structural changes

What it costs you if you skip it

Unconsented work rarely causes a problem on the day you do it. The real damage starts with a mechanical link most owners never think about: every mortgage carries a condition that the property is fully insured, and a bank won't let a buyer draw down a loan, or let you keep an existing one, without evidence of that cover in place. If an insurer won't touch unconsented work, or will only cover it with an exclusion carved out around it, that's not full cover, and a bank can decline to lend against the property on that basis alone. No clean insurance, no satisfied finance condition, no settlement. That single chain kills more sales than any building inspector's report does.

From there it compounds. It's listed as an outstanding issue on the LIM report for any buyer to see. Your own insurer can apply the same exclusion to you right now, as the current owner, not just at resale. And once a buyer's lawyer spots it, it becomes a straight discount or a walked deal rather than a negotiation. I've seen vendors lose real money at exactly that point, it's one of the patterns behind why some North Shore homes sell for less than they should. It's always cheaper to sort the paperwork before you list than to explain it after an offer's already on the table.

Already built without a building consent? Here's what you can do

This is the question I get almost as often as "do I need consent for this," usually a beat later: "what if I already built it?" The answer depends entirely on when the work was done, because 1 July 1992 is the line that splits two completely different pathways.

For anything built from 1 July 1992 onward, the route is a Certificate of Acceptance, or CoA. It's a council process, not a private one, and Auckland Council describes it as giving only limited assurance that unconsented work complies with the Building Code, to the extent the council can actually verify it. That's the catch: the council can only assess what it can inspect or what you can prove with evidence, photos, invoices, producer statements, accurate as-built drawings. Anything closed in behind linings with no supporting evidence can be excluded from the certificate, or require opening up walls to check. Getting a CoA doesn't switch off the council's enforcement powers either, it just becomes something the council will take into account if it ever does act.

For anything built before 1 July 1992, a CoA isn't available at all, because building consents as we know them didn't exist yet. The route there is what the industry still calls a Safe and Sanitary report, sometimes labelled a third-party report. It's prepared privately by an independent building surveyor or suitably qualified inspector, and it doesn't legalise the work or replace a CCC or CoA. What it does is put an expert opinion on the property file confirming the work is safe to occupy and sanitary, which is often enough for a bank, an insurer, or a buyer's lawyer to be satisfied, even though the underlying work was never technically consented.

Neither pathway is a shortcut, and neither is guaranteed to come back clean. If an assessment turns up something genuinely unsafe, you're looking at remedial work and possibly a proper consent on top of that. But doing nothing is worse. It's the difference between disclosing a documented, assessed position and hoping nobody asks.

Quick answers

Does a deck need consent in Auckland?

It's unlikely to, as long as the fall height, the drop from the edge, stays at or under 1.5 metres. Deck height off the ground on the high side isn't the measurement that matters.

Does my pool need a consent?

Most in-ground pools up to 35,000 litres are unlikely to need one for the structure itself. Larger in-ground pools, and above-ground pools outside their own height and capacity limits, will. Either way, the safety barrier is a separate consent that applies almost regardless of the pool's size.

Does repositioning bathroom fixtures need consent?

It's unlikely to, including moving a toilet pan into an adjoining bathroom, or swapping a bath-and-shower-over for a separate shower enclosure and a new bath. That swap doesn't increase the fixture count, a bath-and-shower-over already counts as two fixtures, it's just splitting them apart. A new tiled wet-area shower, or adding fixtures that genuinely didn't exist before, is a different story.

Can I convert my garage without consent by calling it a granny flat or a lounge/bedroom?

No. The consent-free pathway only covers new, detached, single-storey builds up to 70 square metres. Converting an existing garage is a change of use and always needs consent.

Does replacing a garage door with a ranch slider need consent?

Generally not, on its own, it's treated the same as replacing any window or exterior door. It's only once you insulate, line and start using or advertising the space as a bedroom or office that you've triggered a change of use, which does need consent.

Does removing a wall for an open-plan kitchen need consent?

Yes, if the wall is load-bearing, part of the bracing system, or a fire separation element. Get a structural assessment before anything comes out.

What if the work's already done and I never got consent?

It depends on the date. For anything built from 1 July 1992 onward, you apply to the council for a Certificate of Acceptance. For anything built before that date, a private Safe and Sanitary report is the usual route instead. Neither legalises the work outright, but both put a documented, assessed position on record rather than a hidden one.

You'll notice "unlikely to need a building consent" rather than "exempt" throughout this post. That's deliberate: individual site conditions, overlays and the exact scope of a job can shift the answer either way, so treat every item above as a starting point, not a ruling. This is general guidance based on Auckland Council and MBIE rules current as of September 2026. Confirm your specific project with Auckland Council or a licensed professional before you start work.

Before you go

I'm Nish, a residential salesperson here in Mairangi Bay, licensed as a Branch Manager under REAA 2008. I work alongside Nana Li & Charlotte Goudge, also residential salespersons, across the East Coast Bays and the wider North Shore. Between us we track this market street by street, not just suburb by suburb, and consent history on a property is one of the first things we check before we ever put a price on it. Meet the team.

Not sure what's sitting unconsented in your own home? Get a free appraisal.