Waterworld

 Kevin Costner wears circus pants and is a lone wolf mariner type in a world completely submerged in water.  The intro is really cool because all the ice caps melts and take over the Universal studios logo- very fancy for the 90s. 

He stops at a town to buy things and everyone thinks he's super shady because he has a lot of dirt, which is money when everything is water-logged. Somehow all the townsfolk are super dirty looking despite being surrounded by water. He is really into plants and spends all his money on buying the water lady's. 

I think they accuse him of a crime because they don't like him and he's in a cage suspended over water. It's bad timing because a pirate guy that has Jack Black as an assistant comes to the town looking for a girl with a tattoo on her back that could've easily been recreated on paper. 

The pirate guy destroys the town but Kevin Costner escapes with the water lady and the little girl. Then he treats them like shit but somehow he and the water lady fall in love. At some point he shows her he has gills but also cuts her hair at some point. 

There's a big fight with explosions at the end but they eventually find land like the maps says. He's a mariner though so he goes back into the water.