I'll bite. You'd be surprised at the expense involved in creating clean water. In NA, we're particularly lucky to have fairly fresh drinking water, but in oth

I'll bite. You'd be surprised at the expense involved in creating clean water. In NA, we're particularly lucky to have fairly fresh drinking water, but in other parts of the world this isn't the case. However, let's focus on NA for now. Not every city is next to a glacier field, which provides some of the purest water -- mainly because it is from the rain, it is a water source, and because it is difficult to get to it which limits its pollution. The majority of people drink water that is provided by rivers and reservoirs. These sites are easy to get to, which means it is also easy to pollute them with (a) boats, (b) nature, (c) industrial pollutants... the list goes on. The farther the water travels, the more likely it is that it will pick up pollutants. The water that comes out of your tap has some fairly strict healthy and safety laws attached to it, keeping it fairly pure to drink. Even then, there are a lot of nasty bugs in there. Just about every household tap requires water to be potable, which means safe for human consumption. That water you are washing your car with? Drinking water. Sure, it doesn't taste Brita-fresh, but you can still drink it without getting dysentery. So....my point to all this is that access to fresh, clean drinking water is actually very difficult and expensive, and is best thought of as a modern world luxury. If we're putting most of that water into crops and food that will be wasted, we're slowly slitting our own throat and wasting a luxury. All the while, more and more people are occupying the same piece of land, increasing the load on the fresh water supply. Great invention of all time? Sewage systems. Before that, people used to throw EVERYTHING into the same place where they drank. There's a reason people preferred to live upstream. There's also a reason why everyone pre-1900s used to drink beer or tea (heat kills most water-borne diseases). Edit: I forgot to mention groundwater aquifers as a water source, but my point stands.