Just boil it. Run it through a simple charcoal filter to get the chunks out and improve taste.
If you're concerned about toxic contaminates, then reverse osmosis or distillation are your only options. I'm not sure why people don't talk about using distillation more often... Perhaps because it's not as tacticool as reverse osmosis. It takes a little bit of skill to operate a still as well, but as long you throw away the first stuff to evaporate and the last then you've got the basics of it.
If you're concerned about toxic contaminates, then reverse osmosis or distillation are your only options. I'm not sure why people don't talk about using distillation more often... Perhaps because it's not as tacticool as reverse osmosis. It takes a little bit of skill to operate a still as well, but as long you throw away the first stuff to evaporate and the last then you've got the basics of it.