The water radical and the water kanji are the same.
Imagine a lake (i.e. a whole bunch of water). When you think of water, you should try to think of this beautiful lake. It’s sunny, the trees smell nice (imagine a tree smell if you can – the more senses you use the better!) and on that tree there is an awesome tire swing (すい). You get onto the tire swing and you are swinging back and forth. The water is right in front of you, and you are able to use the swing to throw yourself into the water. It’s a lot colder than you expected, and you come back to the surface, gasping for breath. The water gets into your mouth and you taste it. How strange, it’s very, very sweet. Imagine the sweetness of the water and how weird it is (really really sweet, this water is).