Installing a freestanding bath can be a stunning bathroom upgrade, but in New Zealand the answer to whether you can do it yourself depends entirely on which part of the job you're talking about. Positioning and levelling the bath is generally fine for a capable DIYer — but connecting it to the water supply and drainage is restricted plumbing work that must be carried out by a licensed tradesperson.
What the Law Says About Plumbing Work
Under the Plumbers, Gasfitters, and Drainlayers Act 2006, connecting any sanitary fixture — including a bath — to the water supply or to the waste/drainage system is restricted work. This means it must be done by, or under the direct supervision of, a licensed plumber registered with the Plumbers, Gasfitters and Drainlayers Board (PGDB). Doing this work yourself without a licence is illegal and could void your home insurance, create liability issues if something leaks, and result in a fine.
The only plumbing tasks a homeowner can legally carry out themselves are very minor maintenance items — such as replacing a tap washer or a showerhead on an existing fitting — not new connections.
What You Can Do Yourself
While the plumbing connections themselves are off-limits, there is still plenty a handy homeowner can tackle:
- Choosing and purchasing the bath — freestanding baths are widely available at plumbing merchants and retailers like Bunnings and Mitre 10.
- Preparing the floor — ensuring the subfloor is structurally sound and level. A freestanding bath full of water is very heavy (often 200–400 kg), so the floor must be able to handle the load. Check with a builder if you're unsure.
- Waterproofing and tiling — if you're tiling around the bath area, this is generally DIY-able, though the waterproof membrane under tiles in wet areas must comply with the relevant NZ Building Code clauses covering internal moisture and external moisture (check with your council or BRANZ for the applicable requirements). BRANZ has good guidance on wet-area waterproofing requirements.
- Painting and decorating — brands like Resene and Dulux offer moisture-resistant bathroom paints suitable for DIY application.
- Positioning the bath — once your plumber has roughed in the supply and waste pipes to the correct location, you can often place and level the bath yourself before the plumber returns to make final connections.
Does Installing a Freestanding Bath Need a Building Consent?
In most cases, replacing a bath like-for-like in the same location is exempt from building consent under Schedule 1 of the Building Act 2004. However, if you're moving the bath to a new location, altering the drainage layout, or doing significant structural work, a consent may be required. Always check with your local council before starting — rules can vary and it's not worth the risk of unconsented work.
You can find more information on consent exemptions at MBIE Building Performance.
The Plumbing Rough-In: Getting It Right
For a freestanding bath, the plumbing rough-in is critical and must be planned carefully before any flooring or tiling goes down. Key considerations include:
- Waste outlet position — freestanding baths typically have a floor waste or a waste that runs through the floor. The exact position must match your chosen bath's outlet location.
- Water supply — floor-mounted or wall-mounted taps (called floor pillar taps or freestanding bath fillers) need supply pipes roughed in at precise locations.
- Trap and venting — your licensed plumber will ensure the waste trap and any venting comply with NZ Building Code clause G13 (Foul Water).
Get your plumber involved before you finalise the bath position or lay any flooring. A good plumber will rough in the pipes to suit your chosen bath and tap set.
Typical Costs (As a Guide Only)
Plumbing costs vary by region and complexity. As a very rough guide, expect to pay somewhere in the range of a few hundred to over a thousand dollars for a plumber to rough in and connect a freestanding bath, depending on how much pipe work is involved and your location. Always get at least two or three quotes.
When to Call a Professional
You should engage a licensed plumber for:
- All water supply connections (hot and cold)
- Waste and drainage connections
- Moving or extending existing pipework
- Checking that your drainage complies with NZ Building Code clause G13
- Issuing a Certificate of Compliance for the plumbing work (required by law)
You may also want to consult a Licensed Building Practitioner (LBP) if structural floor work is needed. Find qualified local plumbers and builders on tradedirectory.co.nz.
For rental properties, remember that bathrooms must also meet Healthy Homes Standards for moisture and drainage.
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