Bathroom rough in plumbing is the first stage of bathroom plumbing, where a licensed plumber installs the hidden water supply, waste and vent pipes before walls are sheeted or the slab is poured. It happens before waterproofing and tiling, and it fixes where every tap, shower, toilet and basin will sit.
This guide explains what a rough-in is, what happens at each stage, what you can and can’t do yourself and what Sydney plumbers charge. For the whole project budget, see our average bathroom renovation cost guide.
Key points
- A rough-in is the pipework behind the walls and under the floor, installed before the finishes go on.
- It is licensed work: Sydney Water says renovations and replacing toilets and showers need a licensed plumber.
- Get the fixture positions and tap heights confirmed before the plumber starts, because moving pipes later is expensive.
- Waterproofing follows the rough-in and the plumber’s inspection, and the fit-off comes last.
What is a rough in? Rough-in meaning
| Term | Meaning | Why it matters |
|---|---|---|
| Rough-in | Installing the concealed supply, waste and vent pipes | It sets fixture positions and is hard to change later |
| Under slab rough in plumbing | Waste and sometimes supply pipes laid before the concrete slab is poured | Cannot be moved after the slab sets |
| Fit-off | Installing taps, toilet, basin and shower fittings | Happens after tiling and waterproofing |
| Waste and vent | Pipes that remove used water and let air into the system | Prevents gurgling and sewer smells |
| Cert of Compliance | Document the plumber gives you after the work | Confirms the work meets the Plumbing Code of Australia |
- “Rough ins” and “roughin” are other spellings of the same stage that tradies use.
- Rough-in comes before lining and waterproofing, and finish work comes after.
- Everything is positioned to the plan, so tile layouts and vanity sizes must be decided first.
Bathroom rough in plumbing: stages and sequence
Each stage depends on the one before it, and skipping an inspection can cost you later.
- Strip out and make safe: remove old fittings, cap lines and check for hidden damage in older pipes.
- Mark fixture positions: the plumber sets out shower, toilet, basin and floor waste with you against the plans.
- Run waste and vent pipes with a continuous fall to the drain and the correct trap or floor waste.
- Run hot and cold supply pipes to tap and shower positions, with stop taps where required.
- Fix and test: the plumber pressure-tests the supply and checks the waste before the walls are closed.
- Book inspections and waterproofing next; see our bathroom waterproofing membrane guide.
Bathroom plumbing rough in diagram: what goes where
A diagram helps you check positions with the plumber before pipes are fixed. Our bathroom plumbing diagram guide shows the full layout.
| Item | What the rough-in includes | Check before work starts |
|---|---|---|
| Shower rough in plumbing | Hot and cold lines, mixer position, waste to the floor waste | Mixer height and showerhead position |
| Toilet | Waste outlet and cold water to the cistern | Pan type, outlet position and clearance |
| Basin and vanity | Hot and cold supply and a waste outlet | Vanity size, drawer clearance and tap type |
| Floor waste | Drain in the shower or wet area floor | Falls to the waste in the screed |
| Bath | Supply, overflow and waste | Spout position and access to the trap |
Rough-in plumbing under slab and kitchen rough in plumbing
Slab-on-ground homes need the pipes laid before the concrete is poured, which makes mistakes expensive to fix.
- Under slab rough in plumbing places waste lines and floor wastes in the ground before the slab goes down.
- Pipe positions are checked before the pour, because moving a waste after the concrete cures means cutting the slab.
- Timber floors and upper storeys have the rough-in in the floor frame and walls instead.
- Kitchen rough in plumbing follows the same stages for the sink, dishwasher and tap, with waste and supply set to the cabinet plan.
- Plumbing diagram for house on slab drawings show where every pipe runs; keep a copy for the future.
- Take photos before the walls close, so you know where pipes run when you hang a heavy cabinet.
What plumbing can I do myself?
Sydney Water says homeowners who are confident with minor work, such as changing a tap washer, can do it themselves. A licensed plumber is needed for bigger problems and renovations.
| Job | DIY or plumber |
|---|---|
| Changing a tap washer | DIY if you’re confident |
| Plunging a blocked toilet at the bowl | DIY |
| Bathroom rough-in or pipe relocation | Licensed plumber |
| Replacing a toilet or shower | Licensed plumber |
| Repairing leaks in private water pipes | Licensed plumber |
| Clearing a blockage in a private wastewater pipe | Licensed plumber |
- You can help by demolishing tiles and old linings, but ask the plumber what to leave in place.
- Don’t touch water supply or waste pipes yourself; work that isn’t licensed can void insurance.
Bathroom rough in plumbing and council, waterproofing and timing
- Check approvals before you start; our council approval guide explains when you need them.
- Waterproofing goes on after the rough-in is inspected, using products to AS 3740; see our waterproofing shower guide.
- Allow cure time; our waterproofing time guide explains why you can’t rush the membrane.
- Budget for the waterproofing as well; see our waterproofing bathroom cost guide.
- Ask for the Certificate of Compliance at the end, because it confirms the work meets the Plumbing Code of Australia.
- Keep every document for insurance and any later sale of the property.
What a plumber charges for bathroom rough in plumbing in Sydney
| Service (Sydney, Oct 2026, incl. GST) | Price range | Typical |
|---|---|---|
| Call-out fee | $69–$170 | $140 |
| Hourly rate | $92–$230 | $140 |
| After-hours hourly rate | $170–$345 | $255 |
| Toilet repair | $150–$350 | $250 |
- A full rough-in is priced by scope, so ask for an itemised quote (indicative — get itemised quotes).
- Ask whether the fit-off is included or quoted separately.
- Ask about variations so you know what happens if you move a fixture mid-job.
Common mistakes to avoid
- Don’t finalise tile and vanity choices after the rough-in, because fixture positions depend on them.
- Don’t cover pipes before the plumber has tested them; a leak behind a sheeted wall costs far more to fix.
- Don’t skip the floor waste fall, or water pools in the shower.
- Don’t forget access panels for the shower mixer and any trap you may need to reach.
- Don’t use an unlicensed tradie for plumbing; check the licence number before work starts.
Bathroom rough in plumbing FAQs
What is a rough in?
A rough-in is the first stage of plumbing, where a licensed plumber installs the concealed supply, waste and vent pipes before walls are sheeted or the slab is poured. Taps, toilets and basins are fitted later, after waterproofing and tiling are complete.
What is rough in plumbing for a bathroom?
It is the hidden pipework for the shower, toilet, basin and floor waste. The plumber sets out and fixes the pipes to your plans, tests them, then waits for inspection and waterproofing before returning for the fit-off.
What plumbing can I do myself?
Sydney Water says you can do minor jobs such as changing a tap washer if you’re confident. A licensed plumber is needed for renovations, replacing toilets and showers, and repairing leaks in private water pipes. A rough-in always needs a licensed plumber.
How much does a bathroom rough-in cost?
It depends on the layout, access and whether pipes move. A Sydney plumber charges a call-out fee of $69–$170 and an hourly rate of $92–$230 (October 2026, incl. GST). Ask for an itemised quote that separates rough-in from fit-off.
Getting bathroom rough in plumbing done in Sydney
If you’re planning a renovation, we can set out, rough in and test the bathroom plumbing, then hand over a Certificate of Compliance. Go back to the average bathroom renovation cost guide or book a licensed plumber.
