A Plumbing Checklist for Your Bathroom Renovation

Bathroom renovations involve more plumbing decisions than most homeowners expect, and getting them settled early avoids costly changes once tiling and fit-out are underway.

Decide on the layout early

Moving a toilet, shower or vanity to a new position usually means relocating drainage and water supply lines, which is far cheaper to plan before any tiling starts than to change mid-renovation. If you're keeping fixtures in their existing positions, confirm that with your plumber before finalising the layout.

Check the waterproofing scope

Waterproofing is a licensed trade separate from plumbing, but the two need to be sequenced correctly. Confirm with your builder or plumber who is responsible for waterproofing the shower base, walls and any floor wastes before tiling begins.

Plan tapware and fixtures before ordering tiles

Tapware, shower mixers and fixture rough-in dimensions vary by brand and model. Choosing your tapware before rough-in plumbing starts avoids having to adjust pipework later if a chosen fixture needs different spacing.

Ask about water pressure and flow

If you're adding a rain shower head, double shower or additional fixtures, ask your plumber whether your home's existing water pressure and pipe sizing can support them, particularly in older homes with narrower original pipework.

Confirm floor waste and drainage falls

Bathroom floors need the correct fall (slope) toward the floor waste to drain properly. This is set during the rough-in stage, so it's worth confirming it's been accounted for before floor tiling begins, since it's difficult to correct afterward.

Get a clear staging plan

Plumbing for a bathroom renovation typically happens in two stages: rough-in (pipework inside walls and floors, before tiling) and fit-off (connecting tapware and fixtures, after tiling). Ask your plumber to outline both stages and when they need site access for each.