Always carry water purification tablets even if you carry a water filter or have a planned water pick up point. Both can fail. Follow the instructions on the tablet container. Once you are down to 1 liter per person, finding water should become a priority. Err on the side of having too much water instead of too little .
Community use being water used for meals, coffee, and hot chocolate.
Drink between 1 to 2 cups of water an hour when walking to avoid dehydration. Drinking a lot of water at the end of a trek is not as helpful as spreading it out over the trek. Also, drinking a lot of water at once after being exhausted, thirsty, or weak makes some people nauseous. So drink a little a lot of times. You can be slightly dehydrated and not feel thirsty.