Adding H2O before bottling...

Ok, I made a Nut Brown Ale that is slightly high in alcohol content, and my secondary fermenter is only about to the 4.25 gallon mark. Would it be safe to add a half gallon or more water to it and also get more bottles from this batch or is this a bad idea? I would like to drop the alcohol by about 1%. Keep in mind I use only store bought spring water in my beer. Do I still need to boil it like I've been hearing?

You can do that, sure. But you need to remember that you're not just watering down the alcohol, you'll be diluting the flavour as well. I'd pull out a measured sample and dilute it to the same ratio as you would for the whole batch and test the taste first. If you like the result you can go ahead and do the whole batch.

Store bought water or not, I would boil and cool it before adding. No sense wasting all that hard work now for the sake of a couple hours waiting.

BYO had an article about it. (you can find it by googling). They said it is a common practice by commercial brewers.

Boil it to sanitize AND drive off oxygen. You don't want to intentially oxidize your beer.

honestly I wouldn't muck with it unless it tastes bad.