Lightning is NOT attracted to water. On the contrary, lightning will usually hit anything that is protruding from a flat surface, like a pole or a tree. The scary thing about lightning hitting water is the fact that water can conduct electricity. This means that the electric current that the lightning has can be carried through the water, and if you are swimming when lightning hits, you are in trouble. The only reason that lightning may hit water more often than land is because the earth is mainly covered with water, not land.

Information that I found states that there is LESS lightning per area over water than overland. This is due to the ability of land to heat up quicker and be more suitable for lightning strikes. Water takes a long time to heat up, so most water is cool making lightning less likely to strike there. Interesting topic!