How to install a shower drain

🔧 Installing a Shower Drain in Australia — compliant set-out, drainage falls, and waterproofing coordination

What is involved in installing a shower drain in Australia?

Shower drain installation in an Australian bathroom renovation requires accurate set-out, compliant falls, correct connection to the sanitary drainage system, and close coordination with the waterproofer and tiler. Plumbing work in Australia must be performed by a licensed plumber. This guide explains the process and helps you select the right tools and materials.

This guide is written for Australian trade professionals and references the PCA and AS/NZS 3500 principles relevant to sanitary drainage, fixture outlet installation, and floor waste/shower waste positioning.

What skill level is required for shower drain installation?

Advanced — Estimated time: 4–8 hours for drain rough-in and set-up, plus coordination time for screed, waterproofing, and fit-off

What tools are required for a compliant shower drain installation?

What materials are needed for an Australian shower drain installation?

Safety Requirements

Step-by-Step Guide

Step 1: Set out the shower waste position and confirm floor build-up

1️⃣ Confirm layout and datum

Set out the shower drain position from approved plans, screen location, tile set-out, and mixer outlet location. In most renovations, the drain must align with the shower floor geometry and expected tile falls, while also allowing practical access to the sanitary branch.

Confirm:

For central point wastes, set the waste to allow even falls from all sides. For linear/channel drains, confirm whether the system is against-wall or offset, and ensure the floor design supports single-plane or two-plane falls.

💡 For large-format tiles, linear drains generally simplify falls and tile finishing.

Step 2: Select the correct drain type, outlet size, and flange system

2️⃣ Choose a compliant waste assembly

Select a WaterMark-certified shower waste suitable for the application:

Confirm outlet size, commonly 50 mm for shower drainage rough-in in Australian work, unless the design and authority requirements allow otherwise. Match the drain body to the floor construction:

Coordinate the flange detail with the nominated waterproofing membrane system. The flange and membrane interface is critical to wet area performance.

💡 Don’t treat the grate selection as purely aesthetic. Flow rate, cleaning access, tile compatibility, and membrane integration matter more than appearance alone.

Step 3: Open the floor and prepare the drainage path

3️⃣ Prepare substrate and access

Expose the work area by removing existing floor finishes, screed, and substrate as required. In slab work, saw-cut and break out only enough area to install the trap/waste and branch connection without compromising structural elements. In framed floors, lift sheeting and inspect joists, noggings, and service routes.

Check the available depth to accommodate:

Provide a clean trench or cavity for the branch line. Remove rubble and ensure the bedding area is stable.

⚠️ Do not cut structural members or slab reinforcement without engineering approval.

Step 4: Rough in the branch drain with compliant falls

4️⃣ Install the sanitary drainage connection

Run the branch drain from the shower waste location to the existing sanitary drain connection point using PVC-U DWV pipework to AS/NZS 1260 and installation practices consistent with AS/NZS 3500.

Maintain a consistent fall toward the downstream connection. Avoid back-falls, flat spots, and excessive directional changes. Use long-radius fittings where practical to improve flow and cleanability.

Dry-fit first, then check:

Prime and solvent weld all joints in accordance with manufacturer instructions. Support the pipework properly in framed floors to prevent movement during screeding and fit-off.

💡 On renovations, confirm the existing branch size and condition before tying in. Old, poorly graded branch lines are a common cause of slow shower drainage.

Step 5: Position and secure the shower waste body

5️⃣ Fix the waste at the correct finished height

Install the shower waste body at the exact set-out point and height relative to the finished tile level. The grate or tile insert frame must finish flush with the final tile surface unless the manufacturer specifies otherwise.

For point wastes:

For linear drains:

Bed and stabilise the waste body using approved support material so it cannot move during screeding or waterproofing. Protect threaded or finished surfaces from contamination.

Step 6: Check falls, set-downs, and shower geometry

6️⃣ Verify floor drainage performance before close-up

Before the floor is closed or screeded, verify that the waste location allows compliant falls from the shower perimeter to the grate without bird baths or abrupt transitions.

Check:

Use a laser and straight edge to model the finished screed plane. This is especially important for:

💡 If the waste is even 5–10 mm out in height or position, the tiler may not be able to achieve clean falls without lipping or ponding.

Step 7: Test the drainage rough-in

7️⃣ Test before waterproofing and screed

Cap or plug the line and carry out the required drainage test in accordance with site procedures and applicable code requirements. Check all solvent weld joints, the waste connection, and downstream tie-in for leakage.

Then run water through the line to confirm:

Document the test where required for QA or certification.

⚠️ Do not allow waterproofing or screeding to proceed until the rough-in has been verified.

Step 8: Coordinate the waterproofing interface

8️⃣ Integrate flange and membrane correctly

The shower waste must be installed to allow a fully compliant connection between the waterproofing membrane and the waste/flange system. Coordinate directly with the waterproofer on:

Install the puddle flange or proprietary bonding flange exactly as specified by the manufacturer and wet area system. Ensure the membrane can terminate properly without voids, fish-mouths, or unsupported edges around the drain body.

⚠️ A poorly integrated flange is one of the highest-risk failure points in a shower renovation.

Step 9: Support screed formation and protect the waste

9️⃣ Prepare for tile bed and final falls

Once waterproofing coordination is complete, protect the waste opening and grate frame. Confirm the screeder or tiler understands the required finished falls to the drain.

For point wastes, falls usually converge from multiple planes. For linear drains, the screed may run as a single plane if the channel is positioned appropriately.

Check that:

💡 Pre-mark the perimeter screed heights on walls or jambs to avoid guesswork during screeding.

Step 10: Fit off the grate and carry out final water test

🔟 Complete fit-off and performance test

After tiling and curing, install the grate or tile insert and remove all protective materials. Clean the drain body and inspect for tile adhesive, grout, screed residue, or membrane contamination that could restrict flow.

Carry out a final water test by running shower flow across the finished floor and confirm:

Where relevant, verify the bathroom floor waste arrangement and overall wet area drainage strategy.

Common Mistakes to Avoid

Pro Tips

Recommended Tools

🔒 Licensing

Plumbing work in Australia must be performed by a licensed plumber. This guide explains the process and helps you select the right tools and materials. Licensing requirements vary by state, including NSW Fair Trading, VIC VBA, QLD QBCC, and WA Building Commission.