I’m sure the brewers in California are looking at ways to become more creative with their available water and may even be looking at cleaning up and reusing their waste water like this: Why Dump Treated Wastewater When You Could Make Beer With It? : The Salt : NPR
Easy there Jim,
GO DUCKS! 
There was a Brewing TV episode where they used straight lake water and they said they couldn’t tell it was brewed with lake water. So, it could probably be done in the OP’s case.
There could be plenty of things you wouldn’t want to drink in that surface water that you can’t taste… I’m not saying the beer wouldn’t taste good… Just maybe it’s not the wisest idea. I’m sure doing it once and having maybe a pint of it and sharing it all out would be fine… but maybe not so great for you if you drink it all yourself or do it frequently for all your beers…
I could just be paranoid about what these companies put into our air and water (and therefore rain). But I don’t trust it. Then there is also organic pollutants like animal feces and decaying animal bodies etc… YMMV is all i’m saying.
I agree, Dan. For me, it wouldn’t be worth it.
Unless there is some mining activity upstream, I wouldn’t worry about your creek’s water being polluted. Definitely get it tested, though, for common ions. I once brewed a brown ale with water from a friend’s flowing well and it tasted terrible - I later learned that the water had a high iron content, although it tasted alright to drink.
As others pointed out, boiling the water will take care of any concerns. It’s the coolness factor. 8)
For now I think I’ll just say screw it. I guess I could walk up the creek as far as I could to see if anything looks suspicous. Would Ward labs be able to tell me if there were pollutants? From a practicality standpoint, taking water from my creek makes no sense. From a novelty standpoint, it seems worthwhile. Kinda like how breweries/distilleries bragg about their own water source. I could, in essence, makes a faulty boast that my beer was sourced from the crystal NC mountain streams, therefore it must taste delicous, etc.
I believe ward can do pollutants. Just keep in mind that they can’t predict what might be dumped in it later, or what critter might die in it…
…or if someone living along the same stream has cousin Eddie over and he dumps his waste tank into it.
Black Tank IPA?
Hey, I boiled it! It’s good to go!
Use two wirlfloc tablets and it will be fine
Yep that will get all the solids to drop out
Heh saw this new article this morning and it made me think of this… http://www.katu.com/news/local/State-approves-project-to-homebrew-beer-using-recycled-waste-water-300553411.html
You could trace it back using google earth. If you live in a hilly/ mountainous area chances are the stream source is very local. Water can’t run up hill. My guess is its fine. You still want to get it tested to make good beer.
If there is farming activity upstream, it could have pesticide and herbicide runoff contaminants. Not good.
I’ve read that a flowing stream will cleanse itself of poop and other organic contaminants in a few hundred yards. Don’t know if I buy that.
I live in the actual mountain with actual mountain creeks fed by actual mountain springs. No farm land, no one living above me, barely anyone ventures into the land outside of hunting season. I will drink from the actual source of the stream without a thought to pollutants or contaminants. If your situation is live mine you should be fine. If you expect pollutants I still think you can filter the water and still be fine.