Does the plumber need to be on site before tiling starts?

Yes, rough-in plumbing has to be complete and tested before the waterproofing membrane and tiles go down, since walls and floors get sealed up after that.

Can plumbing be relocated in a slab-on-ground bathroom?

Yes, but it usually means cutting and reinstating a section of the concrete slab, which adds cost and time compared to keeping fixtures in their original spots.

Do I need a separate plumber for the fit-off after tiling?

Not necessarily a separate plumber, but it is a separate visit, since tapware, the toilet and shower fittings go in after tiling and waterproofing are finished.

Bathroom renovation: plumbing, drainage and rough-in

Full bathroom renovations usually involve two distinct plumbing stages that a straightforward repair or fixture swap doesn't: rough-in work behind the walls and under the floor before tiling, then the fit-off once fixtures, tapware and the shower base or bath are in place. This page is for anyone planning a full renovation rather than a single repair or replacement job.

Rough-in work covers moving or relocating drain and water supply points if the layout is changing, such as shifting a toilet, splitting a bathroom into separate shower and bath zones, or adding a second vanity. This has to be finished and pressure-tested before the waterproofer and tiler start, so timing with other trades matters.

Because a renovation touches so many fixtures at once (toilet, shower, bath, vanity, sometimes a laundry connection too), it's worth briefing the plumber on the full scope up front rather than booking separate jobs, so pipe runs and drainage falls are planned properly rather than reworked later.

What it costs

Cost is driven mainly by how much the layout is changing. Keeping fixtures in their existing positions keeps plumbing costs down, while moving a toilet or relocating drain points under a slab adds significant cost due to breaking and reinstating concrete. Working with a builder or renovator who coordinates trades can also affect how the plumbing quote is structured.

Top 3 by our score

Ranked from our published scoring of public Google reviews for bathroom renovation plumbing.

1. World of Plumbing and Gas Pty Ltd
5.0★ · 232 reviews

95
2. TPR Plumbing & Gas
5.0★ · 385 reviews

94
3. Southline Plumbing & Gas
5.0★ · 199 reviews

94

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FAQ

Does the plumber need to be on site before tiling starts?: Yes, rough-in plumbing has to be complete and tested before the waterproofing membrane and tiles go down, since walls and floors get sealed up after that.
Can plumbing be relocated in a slab-on-ground bathroom?: Yes, but it usually means cutting and reinstating a section of the concrete slab, which adds cost and time compared to keeping fixtures in their original spots.
Do I need a separate plumber for the fit-off after tiling?: Not necessarily a separate plumber, but it is a separate visit, since tapware, the toilet and shower fittings go in after tiling and waterproofing are finished.

Enquiries from this site's forms may be shared with partner providers who perform the work, and we may receive a referral fee. Rankings and scores here are based solely on our published method and are not affected by referral fees.