We chose not to waterproof the Nugget, because the sprays contain chemicals that many families choose to keep out of their homes. The Nugget fabric is thicker than most of our customers expect, able to hold small messes pretty well until you’re able to clean them up. We do know that accidents happen with little ones, though! To protect your foam from unwanted spills, accidents, and mishaps, we suggest purchasing a Nugget Liner Set.