Get a small filter, the ones made for backpacking are usually outstanding. Iodine tablets work well too, but they make the water taste like crap, and if you screw up with it, concentrated iodine is toxic. Boiling is always the best, but make sure it's for long enough or you can still get things like Beaver Fever if you're up north. I think it's 5 minutes minimum to make sure you won't get it with boiling, which isn't ever as convenient as iodine or chlorine.
Animo non Astutia