Buying an earthquake-prone building: %NBS, the EPB register, and what the September 2026 reform would change
Under the Building Act 2004 as it stands, a building is earthquake-prone if its ultimate capacity would be exceeded in a moderate earthquake, defined in the regulations as shaking one-third as strong as a new building on that site would be designed for as at 1 July 2017, and collapse would be likely to cause injury, death or damage to other property. The familiar 34%NBS line comes from the rating categories in the same regulations, which run from 0% to under 20% and from 20% to under 34%, and from the EPB methodology. Council-issued earthquake-prone building (EPB) notices are recorded on MBIE's public EPB register. A building that is not on the register has simply not had a notice issued against it. It has not necessarily been assessed at all. Media report Parliament passed a Bill on 18 to 19 September 2026 that would remove Auckland, Northland and the Chatham Islands from the system; Royal assent was not confirmed when this was written, so it is not yet law.
Correct as at 19 September 2026. The reform section is conditional until assent and the enacted text are confirmed.
What "earthquake-prone" means in law today
The legal test is section 133AB: ultimate capacity exceeded in a moderate earthquake, plus a likelihood of harm.
Regulation 7 defines "moderate earthquake" as one-third of the 1 July 2017 design shaking for the site. Regulation 8 sets the rating categories on EPB notices: 0% to less than 20%, and 20% to less than 34%.
Once a council identifies a building as potentially earthquake-prone it must request an engineering assessment complying with MBIE's EPB methodology, and the owner has 12 months to provide one, extendable by up to a further 12.
Not on the register is not the same as assessed
The register records notices. A notice only follows a council identifying the building, requesting an assessment and making a determination; if the council never got to that building, there is nothing on the register. Silence on the register tells you the building has not been designated. It does not tell you the building's rating, and it does not tell you anyone has ever calculated one.
An invented example, for illustration: a two-storey 1960s concrete building on a provincial main street in a medium seismic risk area. It is not on the register, the information memorandum says nothing about seismic, and the vendor has no assessment. A buyer who reads "not on the register" as "passed" is relying on a number that does not exist, and if the council reaches the building after settlement, the assessment request lands on the new owner.
So in due diligence, ask three questions in writing: has the building ever had an initial or a detailed seismic assessment, who prepared it and when, and what rating did it give. If the answer is none, budget for one before going unconditional; the commercial building inspection cost guide covers which specialist to commission. The standard ADLS/REINZ agreement (now published with The Law Association of New Zealand, TLANZ) has no seismic condition, so an assessment has to sit under the building report condition or a Further Term your lawyer drafts.
34% is the legal line, 67% is the market's
Industry commentary reports that many banks, insurers and tenants treat 67%NBS as their comfort threshold, and that a rating below their threshold can lead a lender to decline, cap or condition lending. We could not verify any bank or insurer policy document, so treat that as market reporting, not a rule. Ask your lender in writing, early, what rating it needs to see.
What an assessment costs and how long it takes
The only published figures we found are old: an engineering firm director told the Otago Daily Times in 2019 that an initial seismic assessment could cost around $2,000 and a detailed seismic assessment around $50,000. Treat those as an order of magnitude and get a current quote. We found no published turnaround for a voluntary assessment; in practice it depends on the engineer's availability. We could not read the EPB methodology's own competence requirements during this check, so ask who will sign the assessment and confirm it will comply with the methodology.
The September 2026 reform, stated conditionally
The position as we could verify it on 19 September 2026: the Building (Earthquake-prone Buildings) Amendment Bill was reported back from select committee on 9 June 2026. 1News, the NZ Herald and Stuff report it passed its third reading unanimously on 18 to 19 September 2026, quote the Minister as saying the reform saves about $8.2 billion, and report that about 2,900 buildings, roughly 55% of current EPBs, would come off the register. Royal assent had not been confirmed at the time of writing, so the Bill is not law and nothing below is in force; the House may also have amended the text, so the enacted version could differ.
What the Bill as reported would do, if enacted in that form:
Split commencement. Most of the Act would come into force on 1 July 2027. The provisions setting the new seismic zones, including a new section 133AP, and the schedules would come into force the day after Royal assent.
Low seismic zones drop out. Auckland, Northland and the Chatham Islands would be low seismic zones. Under new section 133AP, a building in a low seismic zone ceases to be earthquake-prone, and the council must notify the owner, remove it from the EPB register and remove the notice. The select committee recorded 1,544 Auckland-region buildings classified as earthquake-prone under the current system, dropping to zero.
In medium and high zones, only some buildings stay in. Buildings of concrete or heavy materials, or with unreinforced masonry, would remain, with tiered remediation rather than a single %NBS target.
The %NBS machinery goes. The Bill repeals the "earthquake rating" and seismic risk definitions and revokes regulations 7 and 8. Law-firm commentary notes that lease clauses and lending conditions keyed to %NBS may lose their anchor, so read any %NBS clause in a lease you are inheriting.
What that would mean for a buyer in Auckland or Northland
If assent follows in the reported form, an EPB notice on an Auckland or Northland building would cease to have effect the day after assent and the council would have to remove it from the register. Three cautions. The building itself does not change, only its legal designation and deadline. Lenders, insurers and tenants are not bound by the Act's definition and will likely still ask for a rating. And register updates and notice removal will lag the statutory trigger. Our commercial property due diligence checklist puts seismic alongside the other records checks.
What this doesn't tell you
The reform section is only as current as 19 September 2026. If you are reading this later, check whether Royal assent has occurred and whether the enacted text matches the reported Bill.
The 67%NBS lender convention and the $2,000 / $50,000 assessment figures are from industry and media sources, not from any lender, insurer or engineer's current price list.
A desk check can tell you whether an assessment exists and what it says. Only an engineer's assessment gives the building a rating.
FAQ
What does %NBS mean, and is 67% NBS good enough?
%NBS expresses a building's assessed earthquake capacity as a percentage of what a new building on that site would be designed to. The legal categories sit below 34%; industry commentary reports many lenders, insurers and tenants prefer 67% or more, but that is market practice, not law.
How do I check whether a building is on the EPB register?
Search MBIE's public register at epbr.building.govt.nz. A listing means a council has issued an EPB notice; no listing means no notice has been issued, which is not the same as the building having been assessed or having passed.
Can I get a mortgage or insurance on a building below 34% NBS?
Sometimes, on conditions. Industry commentary reports that a low rating can lead a lender to decline, cap or condition lending, so ask yours in writing during the due diligence period.
What is the difference between an initial seismic assessment and a detailed seismic assessment, and what do they cost?
An initial assessment is a screening exercise and a detailed assessment is a full engineering analysis of the structure. The only published figures we found are from 2019, around $2,000 for an initial and around $50,000 for a detailed assessment.
How long do owners have to strengthen once a notice is issued?
Under the current Act, 35 years in a low seismic risk area, 25 in medium (12.5 for priority buildings) and 15 in high (7.5 for priority buildings), measured from the first notice, with 4 years added to deadlines falling on or after 2 April 2024.
Will the Earthquake-prone Buildings Amendment Bill remove the requirement for my building?
As at 19 September 2026, media report the Bill has passed its third reading but Royal assent was not confirmed, so it is not yet law. If enacted as reported, buildings in Auckland, Northland and the Chatham Islands would cease to be earthquake-prone the day after assent, and in medium and high zones only concrete, heavy-material and unreinforced masonry buildings would stay in the system.
Send us the seismic records
If you have a listing, an information memorandum, a LIM or an existing seismic assessment for a building you are considering, send it through and we will tell you in writing what the records show and which engineer or inspector you need next. Independent analyst, not a valuer, engineer, surveyor, building inspector or lawyer.
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