Water will spin right out, no problem. Just run it a bit if it gets wet. Grass and dirt could be a problem if you wreck, but most of these covers are really sturdy and protect the clutch from damage in a crash. The stock ones, especially the carbon fiber ones, won't. The pressure plate looks like it keeps a lot of stuff from getting to the clutch plates. One thing I did when I installed mine was to also get stainless steel clutch springs, as the stock ones will rust. Oh, and don't get your fingers anywhere near it when it's running!