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A bathroom renovation is one of the best investments you can make in your home. But plumbing is the backbone of any bathroom — get it wrong and everything else suffers. Here is what to expect from the plumbing side of your renovation, from Pete at Water & Gas Worx — PGDB-registered with 17+ years on Auckland tools.
Quick answer: Plumbing for a bathroom renovation in Auckland typically costs $2,000 to $10,000+ depending on scope: $2,000–$4,000 for a like-for-like fixture swap, $3,000–$6,000 for minor layout changes, and $5,000–$10,000+ for a full relayout with new pipe runs. The work runs through four stages — strip-out, rough-in (first fix), waterproofing and tiling, and fit-off (second fix). Water & Gas Worx labour is $155+GST for the first hour and $100+GST per hour after, with all pricing fixed and quoted upfront. Gas work includes Gas Compliance Certificates (GSC) at no extra charge.
When to Involve Your Plumber
The answer is early. Ideally before you finalise your design. Your plumber can tell you:
- Whether your planned layout works with existing pipe runs
- If moving fixtures will require significant pipe rerouting (and extra cost)
- Whether your hot water system can handle the new setup
- If your drainage can support a new shower, bath, or toilet position
Involving your plumber after the design is locked in can lead to expensive surprises.
Stages of Bathroom Plumbing
1. Strip Out
Old fixtures, tiles, and fittings are removed. The plumber disconnects existing plumbing and caps off pipes. This is when hidden issues often appear — old galvanised pipes, leaks behind walls, or non-compliant work from previous renovations.
2. Rough-In (First Fix)
This is the big plumbing stage. New pipe runs are installed for hot and cold water supply, drainage, and any gas connections. Any gas work requires a certified gas fitter and a gas compliance certificate. Pipes are positioned precisely for where your new fixtures will go. This work happens before walls are closed up and tiled.
Getting the rough-in right is critical. Moving a pipe 50mm after tiling means ripping out tiles.
3. Waterproofing and Tiling
Your plumber steps back while waterproofing and tiling happen. Good communication between trades is important here to make sure everything lines up.
4. Fit Off (Second Fix)
Once tiling is complete, the plumber returns to install all the visible fixtures — taps, shower mixers, toilet, vanity, towel rails, and connections. This is the satisfying stage where it all comes together.
What Does Bathroom Plumbing Cost?
Plumbing costs for a bathroom renovation depend heavily on what you are changing:
- Like-for-like replacement (same layout, new fixtures): $2,000 to $4,000
- Minor layout changes (moving a shower or vanity slightly): $3,000 to $6,000
- Complete relayout (moving everything, new pipe runs): $5,000 to $10,000+
These are plumbing costs only — not including fixtures, tiles, waterproofing, or other trades.
Tips to Keep Costs Down
- Keep fixtures in the same positions: Moving a toilet is the most expensive change because it requires relocating the drain
- Choose fixtures before plumbing starts: Your plumber needs to know exact measurements to position pipes correctly
- Deal with old pipes now: If your home has old galvanised pipes, a renovation is the cheapest time to do a pipe replacement since walls are already open
- Bundle hot water upgrades: If your cylinder is aging, upgrading to a continuous flow system during a renovation avoids paying for access twice
Frequently Asked Questions
How much does bathroom renovation plumbing cost in Auckland?
Plumbing for a standard bathroom renovation in Auckland typically runs between $3,000 and $8,000 depending on the scope. A simple like-for-like fixture swap is at the lower end, while moving waste lines, adding underfloor heating, or relocating the shower costs more. We can quote once we see the plans.
Do I need a plumber for a bathroom renovation?
Yes. Any work involving water supply, drainage, or gas requires a licensed plumber or drainlayer by law. You can verify any plumber's licence on the Plumbers, Gasfitters and Drainlayers Board register. Even if your builder is managing the project, the plumbing must be done by a qualified tradesperson. Getting the plumber involved early avoids costly surprises later.
How long does bathroom plumbing take?
The rough-in plumbing (before tiling) usually takes one to two days. The fit-off (connecting fixtures after tiling) takes another half to full day. If you are relocating drains or adding new plumbing points, allow extra time. We coordinate with your builder to keep the project on track.