Water you find in rock pools, in the desert, is very nasty looking. I would have a very hard time making myself drink any of it. You have got to carry something to filter the water, not just purify it. You also need to take what you have and find a stream or lake and get some water and filter it and drink it so you have confidence in it.
It reminds me of when we had to go in the building with teargas in the army. Everyone went in and put on their gas mask. Then the Drill Instructor popped a CS canister. You could see some smoke but you did not feel anything bad. Then we all had to exit the door one at a time. We had to take off our gas mask and talk to the DI before we could exit. We then got a full exposure to the CS gas. It was to give us confidence in our gas mask and to realize its value. When I left the building I has mucus flowing from every opening in my head. Gross stuff!
So take your filter system and get some confidence in it so you will not hesitate to drink the water you have filtered.
I currently carry a Platypus 2 liter water bag and a Sawer in-line filter in my Camelbak. The bag rolls up and the filter and adapter are small and light.