The diagrams below show a bathroom split into four clear zones. In zones 1, 2 and 3, if there is likelihood of a water jet being used for cleaning purposes a minimum of IPx5 is required.
Zone 0 is inside the bath or shower itself and any fittings used here must be low voltage (max 12v) and be rated IPx7 which is total protection when immersed in water.
Zone 1 is above the bath to a height of 2.25m. A minimum rating of IPx4 is required here.
Zone 2 is an area stretching to 0.6m outside the bath and above the bath if over 2.25m. An IP rating of at least IPx4 is required here.
Zone 3 is anywhere outside zones 0, 1 and 2 (subject to specific limits) and where no water jet is likely to be used there is no IP rating required.
The IEE Regulations do not make specific reference to wash basins but in the opinion of The Lighting Association they should be treated as Zone 2 (i.e. IPx4)