More and more phones are waterproof, dust proof, shock proof etc. and for less money as time goes by.
in a few years time they will all be and cases (where still used) will be purely decorative.
I actually have a Sony Xperia which is waterproof (reputedly) so I don't fret over it getting wet as such. I do however, carry it in a cheap neoprene pouch that I got off ebay for about 2 quid just to guard against knocks and drops.