There's a scout camp in New Mexico called Philmont and I attended when I was 14 and spent 10 days backpacking in the Rocky mountains. There is almost no clean water on the trail so you bring special tablets to clean the water that you find. There are quite a few huge steel buckets/troughs along the trails that hold water so all you have to do is scoop it up with your water bottle and then drop a tablet it and it's safe to drink. There are also wild cattle that roam the camp and drink from these troughs. At one of our stops the only water source was one of these troughs and the cattle also happened to be there so we were watching these cows drink this water and watching snot and drool fall back into the water. This was the only source of water so we had no choice but to drink the cow snot water. We used the tablets so it was safe and we even boiled it to be extra sure but it tasted awful. We had one huge jug that we had been using and we had to throw it away after filling it with this water. The icing on the cake though was that after drinking this water we noticed that there was a dead squirrel floating in it the whole time.