Does water affect radio waves

I have to be honest with you. Technically, the answer is yes. Any electromagnetic wave passing within the effective gravitational distance of a large mass, like the sun or a black hole, will bend slightly.

The effect, though, is so slight that it was never even noticed until about 100 years ago. Even then, it was only found because the Theory of Relativity predicted it, so some scientists went looking for it really hard. Otherwise, any discrepancy would have surely been attributed to a margin of error!

In everyday life, the Earth's gravity has no significant effect on radio waves. Our radio systems don't need to take into account its gravitational effect. But when it comes to detecting planets and stars millions of miles away, it certainly does matter.