Vinyl sheets and luxury vinyl tiles are waterproof. While vinyl sheets have fewer seams it is better suited for wet rooms whereas luxury vinyl tiles come as boards or tiles that are placed side by side, which results in many seams.
So, although the boards and tiles are waterproof, if not installed correctly, there is a risk of water seeping through the seams. It is therefore recommended to use a professional vinyl floor installer to ensure your vinyl floor is waterproof.