If you drop your camera in fresh water, don't panic and don't turn it on!
Instead, immediately remove the batteries and pop the camera in a plastic bag. Then fill the plastic bag with silica gel packets and seal it up. The gel packets ought to absorb the moisture inside of your camera.
After a few days, take you camera out and check it for signs of moisture. If it still seems damp, pop it back in the bag with some fresh packets. If it seems dry, pop your batteries back in and try it out.