There are many water treatment options. Some are heavier and there may be lighter techniques, but after years of trial and error, these work well for me.
My preferred way of treating water is Aquamira drops. It’s widely available and easy to use. I rebottle it in small plastic bottles as shown and use the third bottle for my A+B mix.
As a backup, I sometimes carry a Sawyer filter. Be sure to pack the backwash “syringe” in case sediment slows the flow. I use the freezer bag to scoop water from creeks and then pour it into the Vapur folding water bottle before adding Aquamira drops. It’s also easy to pour from the freezer bag to the Sawyer squeeze bag when needed.
I carry a Platypus 70-oz. water “bottle” that doubles as the base of my pillow at night. I blow it up and put inside a fabric sleeve along with extra clothing. It’s very comfy! I rarely use the Platypus for water unless camp is far from the nearest source or I’m hiking in dry conditions.
That’s about all I have to say about water other than be sure you have a plan for finding it on the trail. Little blue lines on the map don’t guarantee H2O will be there. Hikers who live in the area you’re going to walk can often give you an idea about water levels. When in doubt, cache water at road crossings before your trip. Just be sure to pick up after yourself following your trip.
If you have water treatment tricks to share, please comment or email me. I’m always open to new approaches.