Some long-distance hikers carry Aquamira drops. It's a two-part system that leaves little trace of flavor after it's activated. It takes at least 20 minutes to work.

I carry that on my bike trips, but seldom use it. Where I travel, it's usually pretty easy to find pure natural water, either from a developed well or spring, and/or above pasture and civilization.

On a recent two-month cross-US trip with much stealth camping, I used water treatment once. It's definitely something I could have done without, but at such a low cost and weight penalty, I carry it anyway.