The plumber sees your renovation twice: bare walls and finished ones.
Renovation plumbing is a project, not a callout: rough-in while the walls are open, fit-off when the tiling is done, quoted as a fixed price with the plumbing line item running $3,000–$8,000 on most jobs. The expensive mistakes all happen before work starts: moving fixtures without checking consent, closing walls around old galvanised pipes, and buying fixtures for a pressure system you do not have.
Is this your stream?
A full refresh, a layout change, a new bathroom in an old villa, or a renovation where the plumbing rough-in has to happen before anything closes up. Quoted as a fixed-price project with rough-in and fit-off stages.
Swapping a tap, a toilet or a vanity in the same position is a standard plumbing visit at hourly-plus-callout rates, not a renovation. If no wall is opening and nothing is moving, book a repair instead of a project.
What it costs in Wellington
The published tiers
Southern Plumbing publishes its bathroom renovation tiers: budget refresh $12k–$18k, mid-range $20k–$35k, premium $40k–$70k+. MoneyHub's NZ guide puts the average renovation around $10,000, with a small-bathroom refresh at $1,500–$6,000.
The plumbing component
Southern's own guidance is that plumbing adds $3,000–$8,000 to most bathroom jobs. NZ-wide guides (Unicorns) put bathroom renovation plumbing at $3,500–$8,000, quoted as a fixed price rather than hourly.
What moves the number
Keeping fixtures in place is the single biggest saver, because moving them means new supply and drainage runs. Old galvanised or earthenware pipework found behind the walls adds cost, but replacing it mid-renovation is far cheaper than reopening finished walls later.
Wellington providers, compared
Six providers that do renovation plumbing, grouped by what they are best at. Hover a row for the detail that matters.
Common mistakes
Moving fixtures without checking consent: adding fixtures or changing the layout in a wet area can trigger building consent. Confirm with your council before the plumber roughs in, because retrofitting consent is the expensive version.
Using unregistered trades for the restricted parts: the plumbing and drainlaying in your renovation is restricted work. Check the PGDB register, and keep the certification paperwork for insurance and resale.
Not budgeting the plumbing separately: Southern's published figures put plumbing at $3k–$8k on top of most jobs, and NZ guides (Unicorns) agree at $3,500–$8,000. A quote that hides the plumbing line inside a single total is hard to compare.
Closing walls around old pipes: if the villa still runs galvanised supply or earthenware waste, the renovation is the cheapest moment you will ever have to replace it. New tiles over failing pipes is a renovation you will buy twice.
Choosing fixtures before confirming pressure: low-pressure systems in older Wellington homes limit tapware and shower choices. Maxey does mains pressure upgrades; have the pressure conversation before the fixture shopping.
No written fixed-price scope: renovation plumbing is quoted as a fixed price per project, not hourly. Get the scope, the inclusions and the variations process in writing before work starts.
FAQ
How much does a bathroom renovation cost in Wellington?
Southern Plumbing publishes tiers: budget refresh $12k–$18k, mid-range $20k–$35k, premium $40k–$70k+. MoneyHub's NZ bathroom guide puts the average around $10,000 with a small-bathroom refresh at $1,500–$6,000, and CheckMyBuilder starts NZ renovations from $8,000. The plumbing component specifically adds $3,000–$8,000 on most jobs.
Do I need building consent for a bathroom renovation?
A like-for-like refresh generally does not. Adding fixtures, moving the layout, or changing drainage in a wet area can trigger building consent. Your plumber should flag it, but the obligation sits with you as the owner: check with your council before rough-in.
How much of the budget is the plumbing?
Southern's published guidance is that plumbing adds $3,000–$8,000 to most bathroom jobs, matching the NZ-wide guide range (Unicorns) of $3,500–$8,000 for bathroom renovation plumbing. Moving fixtures and upgrading old pipework push it to the top of the band.
How do I keep the cost down?
Keep the layout. Every fixture that stays in place avoids new drainage and supply runs, which is where renovation plumbing money goes. Refresh the surfaces and fixtures, spend on the plumbing only where the old system genuinely needs it.
Should the plumber coordinate the other trades?
It depends on the firm. End-to-end operators like Harbour City run plumbing, gasfitting and fit-off as one job, which suits owners who want a single point of accountability. Otherwise you or your builder coordinate, and the plumber roughs in and returns for fit-off around the other trades.
Budget $12k–$18k for a refresh, $20k–$35k mid-range, $40k–$70k+ premium on Southern's published tiers, with the plumbing line adding $3,000–$8,000. Harbour City runs end-to-end, Hutt Gas brings a track record back to 1992, Garcia and Ka Pai are the smaller hands-on teams, Southern publishes the budget tiers, and Maxey bundles the mains pressure upgrade while the walls are open. Keep the layout, check consent before rough-in, and get the fixed-price scope in writing.