When I perform home inspections and see whirlpool tubs installed and being used as a tub and shower combination one of the things I look for is to see if it has been installed properly. The most common problem is that do not have the outer flange that turns up and goes behind the tile substrate like most tubs do. Attention to details in the installation for this type of application is critical towards preventing water damage.

You can check for leaks simply by aiming the shower head around the perimeter and inspecting for leaks in those areas. As shown in the picture below, the wood floors in the adjacent rooms would most likely have warped in a few weeks, depending on how many people & how often they took showers. In this case, luckily all that needed to be done was to soak up the water.