The mattress cover felt nice to the fingers.  I was large enough to easily go over a mattress, AND 3 inch mattress foam pad........... with space and stretch to spare.  I would not hesitate to buy it for a much thicker mattress and mine was not a thin mattress.  I cannot supply any information about how water proof this cover is as I felt it would be a bad idea to pour water on a bed with new pad and foam mattress to answer the question...  AND I loved that I could take this cover off and expect to fit ANY MATTRESS NO MATTER HOW THICK OR TALL OR OVERSIZED it might be.