I don't know why folks are so concerned about "not answering this question" when the information has been in the public domain for years.
Check with the Emergency Managemant Agency Center near your home. they have government publications with instructions for treating suspect water.
First, no untreated water anywhere in the U.S. is considered "safe" in our modern day. All agencies and authorities recommend that ALL WATER be treated as polluted before dringing.
The recommended standby is and always has been boiling for at least 5 minutes.
Chemical purification is second choice. Use tablets for the purpose or use two drops of clorine bleach per quart. Too much bleach is dangerous. The bleach can poison you. The limit recommended is two or three drops.
That will remove any organic infestation.
Chemical pollutants are another matter. They require filtering. Some are particles of molecular size and pass through any know filter.
Water comming out of the rocks went into the rocks from somewhere, with its load of chemicals and bacteria. In my area most of the wells have to be filtered and treated before the water can be consumed. Water bubbling straight out of the rocks can get you in deep trouble.
This is espically true if you are out in the bush with no quick access to transport and hit with stomach cramps and the trots.
This is one area were no one recommends taking any chances or being PC exclusively. Do what you have to do to stay hudrated and healthy.
Go to Bass Pro, RMI, Cabellas or any good wilderness center where backpacking supplies are available and buy what you need. Pills, filters, chemicals, whatever it takes.
The other best scource for information on any normal outdoor questions we trekkers face can normally be answered by the old standby, THE BOY SCOUT HANDBOOK. It has good common sense information gathered from a century of documentation and some of the information has not changed since the turn of the last century. Much of their information is PC and usable on the trail, not all, but a lot. Many of the How Too articles in our reenactment publications are lifted straight from the BSH pages. They have been telling people in the bush to boil their water for over 100 years.
Oh yea, the scrubed clean yuppie dude in the neat pressed and creased bush jacket on the TV outdoor show said to boil your water, and use tablets and filters too!
but having a few years of experience I'd suggest in all cases of using surface water to strain then boil 10-15 minutes and THEN add bleach while the water is cooling. Straining gets rid of the "big" stuff like particulate matter and most flukes. Boiling then will kill off the giardia and Cryptosporidium parasites which are resistant to the bleach, which will then kill most everything else.
