This cover is NOT waterproof! My little dog (the night before she died) became ill and peed the bed. Unfortunately it went through the coverlet, blanket, sheets,  (NOT) waterproof mattress cover onto our very expensive mattress. We cleaned it up as quickly as possible - and finally got the stain ( smell) out. 
I suppose I should have done a plain water test upon arrival of the mattress pad... although it never occurred to me. 
Fits well.