A bathroom plumbing rough-in generally takes one to three days for a licensed plumber in New Zealand, though this can stretch longer for complex renovations, difficult access, or older homes with outdated pipework. Understanding what's involved helps you plan your build or renovation realistically and avoid costly delays.
What Is a Plumbing Rough-In?
The rough-in stage is when a plumber installs all the supply pipes, waste pipes, and vent stacks before the walls and floors are closed up. No fixtures — no toilet, basin, shower, or bath — are fitted at this point. The rough-in creates the hidden framework that everything else connects to later.
Typical rough-in work includes:
- Running hot and cold water supply lines to each fixture location
- Installing waste and drain pipes (usually uPVC) to the correct falls
- Setting vent pipes to comply with NZ Building Code clause G13 (Foul Water)
- Positioning rough-in points (stub-outs) for the toilet, basin, shower, and bath
- Coordinating with the builder for correct wall framing and floor penetrations
How Long Does Each Part Take?
Here's a rough guide to time spent on each element of a standard single-bathroom rough-in:
| Task | Approximate Time |
|---|---|
| Supply pipe runs (hot & cold) | 3–6 hours |
| Waste and drain pipework | 4–8 hours |
| Vent stack installation | 2–4 hours |
| Shower/bath waste and trap | 1–3 hours |
| Toilet rough-in | 1–2 hours |
| Inspection prep and tidy-up | 1–2 hours |
These are broad guides only — actual time will vary based on your specific job.
Factors That Affect the Timeline
Several things can make a rough-in faster or slower:
New Build vs. Renovation
A new build is generally quicker because the framing is open, access is easy, and there are no existing pipes to work around. A renovation often involves cutting into existing walls or floors, removing old pipework, and dealing with surprises like corroded copper, cast iron drains, or non-compliant previous work — all of which add time.
Bathroom Size and Fixture Count
A small ensuite with a shower, toilet, and basin is simpler than a large family bathroom with a freestanding bath, double vanity, and separate shower. More fixtures mean more pipe runs, more waste connections, and more time.
Access and Location
Ground-floor bathrooms with a suspended timber floor or easy subfloor access are usually straightforward. Upper-floor bathrooms, concrete slab construction, or bathrooms positioned far from the main drain stack can add significant time and cost.
Compliance and Inspections
In New Zealand, bathroom plumbing work typically requires a building consent if it involves new or relocated drainage. Your plumber will need to coordinate a council inspection of the rough-in before walls are closed. Check with your local council about consent requirements — some minor work may fall under Schedule 1 exemptions, but always confirm before starting.
All plumbing and drainlaying work in NZ is restricted work under the Plumbers, Gasfitters and Drainlayers Act 2006. It must be carried out or supervised by a licensed tradesperson registered with the PGDB. This is not optional — unlicensed plumbing work is illegal and can void your home insurance.
What Happens After the Rough-In?
Once the rough-in passes inspection, the builder closes up the walls and floors. The plumber returns for the second fix (also called fit-off) to install the actual fixtures — toilet suite, basin, tapware, shower mixer, and so on. This stage usually takes another half-day to a full day for a standard bathroom.
Can a Homeowner Do Any of This Work?
In short: very little. Under NZ law, connecting or modifying any sanitary plumbing, drainage, or water supply pipework is restricted work. A homeowner cannot legally carry out rough-in plumbing themselves. You can do non-plumbing tasks like painting, tiling (once the rough-in is done), or installing vanity cabinets, but leave all pipe work to a licensed plumber.
For more on what's restricted, see the PGDB's guidance on restricted work.
When to Call a Professional
You should engage a licensed plumber at the design stage of your bathroom project — before framing begins if possible. Early involvement means the plumber can advise on pipe routes, drain falls, and fixture placement to avoid expensive changes later. A good plumber will also manage consent documentation and inspection scheduling on your behalf.
If you're renovating an older NZ home (pre-1980s especially), budget extra time for the plumber to assess existing pipework. Galvanised steel supply pipes and clay or cast iron drains are common in older homes and often need replacing to meet current NZ Building Code standards.
You can find qualified, local plumbers in your area right here on tradedirectory.co.nz.
Master Plumbers
