There is no official minimum size for a wet room, but guidelines would suggest that a surface area of 1.5m x 1m is the smallest that could comfortably accommodate a toilet and basin.
It should also be noted that a wet room of such dimensions would need to be entirely waterproofed, for the protection of all fixtures and fittings surrounding the shower space.
For a more detailed insight into compact wet rooms, take a look at our dedicated blog, How To Introduce Small Wet Room Ideas To Your Home.
