Privatizing water has caused serious social and economic issues in other countries, and the same could be expected in the United States. Privatization raises the price of a product, as we in the United States experienced with the privatization of gas and electric services. Personally my bill went from $20-90/month under the government controlled gas and electric to an unpayable $200-300 in one place that I lived, and that was with energy saver products everywhere. If the same thing were to happen with water it would be one more thing that many could not afford, and water is necessary for survival, so it should remain part of the government infrastructure.
With regard to water privatization, private investments should be avoided. To illustrate this point, consider private political campaign donations. Politicians of late have become driven by making promises to such donors, sometimes without regard to whether these promises can be kept. I would see a similar situation occuring if water were to be privatized. Those with control to this resource, which should be a universal utility, could fall prey to feeling pressure from large private donors. This could, in turn, create a society in which the distribution of water could follow the distribution of wealth. Public/government control of water should remain as such in order to avoid the pitfalls described herein.