The way that these showers are designed helps control the flow of water. Namely, the placement of the curbless section and the installation of a proper door or curtain is enough to keep the water contained. Of course, the biggest reason that these showers contain water so well is that the floors are sloped toward the drain, which is always installed further away from the curbless entry when possible. That way, it will require maximum effort for water to get out of the shower.