A typical minimum fall to a shower drain is around 1:80 to 1:100 (roughly 10–12 mm per metre), though many specifications use 1:60 to 1:80 for showers to ensure water clears quickly. Local building codes set the enforceable minimum — always check the applicable code for the project location.
Why the range varies
| Factor | Effect on required fall |
|---|---|
| Tile format | Large-format tile needs more fall to avoid lippage and pooling |
| Tile surface | Smooth or polished surfaces drain faster; textured surfaces hold more water |
| Drain length | A long linear drain needs less fall across the floor |
| Distance to drain | Water must travel further on large floors — more fall needed overall |
| Level access / wheelchair | Fall must stay within accessibility limits |
| Local code | Overrides general practice — check before specifying |
Linear drain vs point drain
- Linear drain — fall in one direction only. The maximum travel distance equals the depth of the shower from the drain.
- Point drain — fall in four directions. Water travels diagonally from the corners, so the total fall needed is usually greater, and the tile must be cut to four planes.
This is one reason linear drains suit level-access and barrier-free showers: the single-plane fall can be kept shallow.
Practical points
- Confirm the fall is measured from the furthest point of the shower floor to the drain, not the average.
- Check the fall after tiling, not just at screed stage — tile thickness varies.
- Water test before handover; pooling more than a few minutes after the shower stops indicates insufficient fall.
- For large-format tile, additional fall may be needed to prevent ponding on the tile face itself.
Related: minimum installation depth · common installation mistakes