It's like with any other natural resource. We (civilization) use it, abuse it, and misuse it. Then... when shortages start peeking around the corner, we start wringing our hands, fighting with each other, and we can't even agree on whether it's a problem or not. Unfortunately, foresight sometimes isn't one of our strong points as a society in general. If it won't be a problem by next week... then screw it. It's not important enough to worry about.

I've been to small, tropical islands, such as Aruba, where all their water comes from desalination plants. Aruba has no natural fresh water supplies, so this is their only source of fresh water. Obviously, this is not the answer for everyone.

I agree with Kirk in that it will likely become the cause of regional conflicts, if not global ones.