Do you need a building consent for a bathroom renovation?
Most bathroom renovations that keep the same fixtures in the same places are exempt under Schedule 1 of the Building Act. What the two clauses actually say, and what tips you over into needing consent.
By Bathroom Renovation NZ
Key takeaways
- Schedule 1 clause 12 of the Building Act exempts building work in connection with internal linings or finishes of any wall, ceiling or floor of an existing dwelling.
- MBIE Determination 2024/054 (2 October 2024) decided that a wet-area membrane under tiled shower walls is part of those internal linings, so replacing a tiled shower in an existing home did not need consent.
- Schedule 1 clause 35 exempts alterations to existing sanitary plumbing, provided the total number of sanitary fixtures in the building does not go up and no specified system is modified or affected.
- Clause 35 sits in Part 2 of Schedule 1, which only covers plumbing done by a person authorised under the Plumbers, Gasfitters, and Drainlayers Act 2006.
- Exempt does not mean unregulated: building work must comply with the Building Code whether or not consent is obtained.
Usually not, if you are replacing what is already there in the same place. Schedule 1 clause 12 of the Building Act 2004 exempts work on the internal linings and finishes of an existing dwelling, and MBIE Determination 2024/054 decided that includes the wet-area membrane under a tiled shower. Clause 35 exempts alterations to existing sanitary plumbing as long as the total number of sanitary fixtures in the building does not increase and no specified system is affected. Add a fixture, and you need consent.
What clause 12 actually says
The wording is short. Schedule 1, clause 12, headed Internal linings and finishes in existing dwelling, exempts “building work in connection with any internal linings or finishes of any wall, ceiling, or floor of an existing dwelling”. That is the whole clause. There is no carve-out for wet areas, and none for membranes.
That last point was the argument in MBIE Determination 2024/054, decided on 2 October 2024. The owners of a house near Akaroa argued that installing waterproof membranes under tiled shower walls was critical building work that needed consent, and pointed at MBIE's own published guidance saying so.
The determination went the other way. For the two tiled showers, it found, “the internal linings include the backing substrate attached to the timber framing, the wet area membrane applied to the substrate, the tiles adhered to the wet area membrane, and associated fixings, adhesives, and grouting”. Because the building was an existing dwelling and the work involved removing the old linings and installing new ones, the membrane work fell inside clause 12. It also noted that MBIE guidance is issued under section 175 of the Act, which says such information is guidance only and does not supersede the Act or its regulations.
What clause 35 actually says
Clause 35, Alteration to existing sanitary plumbing (excluding water heaters), exempts “alteration to existing sanitary plumbing in a building, provided that the total number of sanitary fixtures in the building is not increased by the alteration; and the alteration does not modify or affect any specified system”. Water heaters are specifically excluded.
Two things get missed about clause 35. The first is where it sits: Part 2 of Schedule 1 is headed “Sanitary plumbing and drainlaying carried out by person authorised under Plumbers, Gasfitters, and Drainlayers Act 2006”. The exemption is conditional on who does the work. The second is the fixture count. It is the count for the whole building, not the room. Moving a toilet three metres keeps the count the same. Adding a second one does not.
A decision table
| What you are doing | Consent? | Which clause |
|---|---|---|
| Swapping a vanity, toilet or tapware in the same position | Normally no | cl 35 (and cl 32, repair and replacement) |
| Stripping the linings, laying a new membrane and retiling | Normally no | cl 12 |
| Replacing a tiled shower in the same place | Normally no | cl 12 + cl 35 |
| Moving the shower or toilet within the room | Normally no, if the fixture count is unchanged | cl 35 |
| Adding a second toilet, basin or shower | Yes | Outside cl 35: the fixture count goes up |
| Adding an ensuite | Yes | Outside cl 35, and usually structural too |
| Removing or altering a wall | Yes | Restricted building work: needs an LBP |
| Anything that modifies or affects a specified system | Yes | Expressly outside cl 35 |
Auckland Council's own renovation guidance takes the same shape from the council side: it lists adding new sanitary fixtures, drainage changes and structural work as things that generally need consent, and like-for-like replacement in the same position as work that generally does not.
Exempt still has to meet the Building Code
This is the part that costs people money later. Determination 2024/054 records the rule plainly: building work must comply with the Building Code to the extent required whether or not a building consent is obtained. The same determination found the two showers had failed Building Code clauses E3.3.4, E3.3.5 and E3.3.6, because cracked grout let water into the concealed space behind the walls. No consent was needed, and the work was still non-compliant.
So exemption removes a council process, not a standard. That is why we photograph the membrane before tiling and hand you the product data and installation instructions: with no council inspection in the chain, those photos are the only record that exists. See what records to keep for exempt bathroom work.
What a consented job adds
Superior Renovations publishes Auckland figures for the consent side: a mid-range job that needs consent runs $1,000–2,500 in fees and adds 2–3 weeks; structural changes, wet rooms or wall removal run $2,000–3,500 and up and add 3–4 weeks. It also cites a fixed fee of $354 for Auckland minor plumbing work under $5,000 with a producer statement. Those are one company's summary of Auckland Council's schedule, not the council's own figures, and every council sets its own. Treat them as an order of magnitude and confirm yours.
Exemptions apply to the work as it actually is, not as it is described on a website. Check your own job with your council before anyone starts.
Questions
Does a tiled shower need a building consent in New Zealand?
Usually not, if it replaces one in an existing dwelling. MBIE Determination 2024/054 (2 October 2024) decided that the wet-area membrane, substrate, tiles, fixings and grout are all internal linings within Schedule 1 clause 12, so installing them did not require consent. The determination also states that MBIE's contrary guidance is guidance only and does not override the Act.
Does exempt mean nobody checks the work?
Yes, and that is the risk. There is no council inspection on exempt work, so the only record of what went in behind the tiles is the one your builder makes. Determination 2024/054 found showers that needed no consent and still failed Building Code clauses E3.3.4, E3.3.5 and E3.3.6.
Can I do the plumbing myself to save money?
No. The Plumbers, Gasfitters and Drainlayers Board states that homeowners cannot fix or unfix sanitary plumbing. And the Schedule 1 plumbing exemptions sit in a Part that only applies to work carried out by a person authorised under the Plumbers, Gasfitters, and Drainlayers Act 2006, so doing it yourself would take the job outside the exemption as well.
What is a specified system?
A system listed in the Building Act regulations that a building's compliance schedule covers, such as a mechanical smoke-control or automatic sprinkler system. Standalone houses rarely have one; apartments often do, which is why apartment bathrooms are treated differently. Clause 35 expressly does not apply where an alteration modifies or affects one.
Who decides whether my job is exempt?
You do, and you carry the consequences of getting it wrong. That is why we put the clause and the reasoning in writing in the measure-and-design visit, rather than saying a job is 'usually fine'. If it is marginal, the answer is to ask your council in writing before anyone starts.
Sources
- Building Act 2004, Schedule 1 (legislation.govt.nz)
- MBIE Determination 2024/054, 2 October 2024 (PDF)
- Auckland Council, kitchen, bathroom and home renovations
- Auckland Council, minor plumbing alterations
- Plumbers, Gasfitters and Drainlayers Board, advice for consumers
- Superior Renovations, bathroom renovation cost Auckland
Published 16 September 2026, last updated 16 September 2026 by Bathroom Renovation NZ. Every figure and rule on this page is quoted from a source we read in full on the checked date. See our editorial policy.