Water pollution by small users is rampant. There are numerous springs and small streams where they let their cattle use as neccessary. The water would support trout and other wildlife but is dangerous to us.
Cattle ruin a lot streams this way. It now not legal but no one presses it generally. There are many National Forest that has several streams that flow through and cattle, on just a few acres, on private land ruin the water. It looks clean but don't stand in it with a cut on your leg.
It truly is aggrivaiting, that the head waters, of a local little river, arise, from a large spring is pristine until at the foot of the mountain a few folks let their cows and pigs ruin the stream. Down stream other contribute to what would be a very, and was 25 years ago, healthy water way.