Fresh water is actually in increasingly short supply globally. What's funny is that while the "green" types wail and gnash their teeth over carbon emissions, cause y'know that's all trendy right now, growing water supply problems are far more dangerous.
Basically, in a very simplified version, it works like this. We're heavily dependent on underground supplies of water called aquifers. When everything is functions properly, the whole water cycle thing we all learned about back in high school science keeps the amount of water in these basically stable. However, in several areas globally the amount of water we're pulling out of the aquifers has become considerably greater than their ability to replenish themselves. For example, the Ogallala Aquifer, which sits beneath a large portion of the central US and provides not just drinking water but also farm irrigation is likely, at present usage levels, to be dry within 25 years. The problems are even more pronounced in part of Asia, such as parts of south India where the aquifers are going dry so fast that the amount of land they're able to irrigate has been basically cut in half in the past decade.