I've posted refractive materials many times. Each is in context of some specific scenario, and so using one of them without understanding why/when is somewhat of a problem. This is why I don't just have glass shaders sitting on my site. It requires some thought in choosing which to use and what values to put in. Forum threads provide the context and explanation.

Nevertheless, the basic shader is identical to the car paint - just use Refract instead of Diffuse.

Water is nearly an ideal material having a naturally "polished" surface of utter perfect flatness (microscopically - of course there are waves but that's not going to change the nature of the reflections, just the direction). So you can use this shader which is slightly simpler. The addition of bump or displacement would apply when the water requires waves or ripples.

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)