In general, the water inside the park is drinkable, as it comes directly from nearby snowmelt. What is NOT recommended is collecting water near the refuges, because there is human presence very close to those water sources. We do NOT recommend taking water from the Ascencio River until you have passed the Chileno Refuge (upstream), nor from the Francés River until after passing the Italiano campsite (upstream). All other water sources are safe to drink without issues. If you are traveling with a guide, they will indicate where it is safe.