You definitely must treat water. Much of the trek is in grazing land.
Some make a distinction between these two:
- Water filter removes protozoa & most bacteria
- Water purifier removes protozoa & bacteria and deactivates viruses
Viruses are too small to be filtered so purifiers add something to disinfect them.
Make sure your purifier is well maintained & frequently cleaned.
You must either filter, boil, use iodine or water purification tablets.
One guide recommended we boil for 10 minutes! as water boils at a lower temperature at high altitude.
We filter.