It may shock you to know this but a camera can still be damaged by water in some manner, just like any other waterproof product in the world. Clearly, you know if you do not abide by the waterproof rating that your camera could become compromised. But, it goes far and beyond this and if you are not careful, you could actually end up damaging your camera. Here is what you need to avoid doing, no matter the waterproof rating.
Firstly, try not to leave your camera underwater for excessive amounts of time. Each camera will be different but just try and have an internal clock as too much exposure to water can still end up damaging the appearance of a camera. Also, do not directly pour water on the camera from a faucet or garden hose. Lastly, and of course, do not use harsh chemicals when you clean the camera.