Shouldn't "Water is clear" be an accepted solution as well, if you interpret the article as referring to something general ?
I'm afraid that "light" makes little sense here. A French person who said l'eau est claire would be referring to the water's clarity and not that it was a light color.
How should I decide whether to use 'claire' or 'clair'? Isn't water masculine? Or is 'claire' determined by something else?
"Eau" looks like a masculine word as most words ending with "eau" are masculine. However, it is actually feminine.
Never-mind, I just noticed. The 'clear' is describing 'pink', which is masculine.